Deoxyribonucleic acid (DNA) functions as the blueprint of life as it contains essential instructions for the development, operation, growth, and reproduction of all living organisms (1). Organisms utilize cell division process to grow from fertilized egg to a multicellular adult. Throughout an organism's lifespan, the health of tissues and organs is maintained through a continuous cycle of cell replacement. In this cycle, worn-out or damaged cells are systematically replaced with new, healthy cells. When a cell divides, each new cell requires an exact copy of the DNA to function correctly (1). DNA replication and repair processes ensure that each daughter cell receives the same genetic information as the parent cell, which is essential for the survival and proper functioning of all living organisms (2). DNA sequence changes occur through two fundamental mechanisms: germline mutations inherited from parents and somatic mutations acquired during an individual's lifetime (3). Germline mutations are present in all cells and can be passed to offspring, underlying hereditary conditions. Somatic mutations occur post-conception and can be caused by various factors including internal factors such as cellular metabolites, replication errors, and spontaneous chemical changes and external factors such as ionizing radiation, chemical mutagens, environmental pollutants, and lifestyle factors (3, 4). Understanding these distinct mutation types is crucial as they require different analytical approaches. Germline mutation analysis typically involves comparing an individual's sequence to population databases, while somatic mutation analysis often requires comparing affected tissue to unaffected tissue from the same individual. Regardless of type, mutations in genetic information can lead to complex diseases and disorders such as cancer (1). To detect susceptibility, initiation, and progression of such diseases at early stages, scientists perform large-scale DNA sequence analysis (5). Through DNA sequence analysis, scientists can decode the intricate genetic data by uncovering the origins of genetic mutations and disorders (6). In addition, this analysis is crucial for the development of targeted therapies and the advancement of personalized medicine (1).

DNA sequence analysis through traditional wet-lab experiments is expensive and time-consuming (7, 8). This is because wet-lab experiments require specialized equipment, e.g., PCR machines, and costly reagents (e.g., enzymes and chemicals). Detailed experiments on multiple patient samples may take weeks or even months. Moreover, experimentation requires careful execution and validation to prevent incorrect interpretations of genetic mutations due to errors or inconsistencies. The influx of next-generation sequencing and high-throughput approaches has given rise to huge sequences data. This abundance of genomic information has created both opportunities and challenges for comprehensive analysis. To expedite genomics sequence analysis, researchers are analyzing publicly available sequences data by harnessing the capabilities of Artificial Intelligence (AI) methods. It is important to mention that AI approaches serve to augment rather than replace experimental methods in DNA sequence analysis. For example, in precision medicine, AI models trained on large genomic databases can help to interpret patient-specific data by identifying relevant patterns and potential functional impacts. However, patient-specific experimental data remain essential, particularly for understanding unique aspects of individual cases such as tumor mutations. Thus, AI methods provide a valuable tool for generating hypotheses and guiding experimental design while working in concert with traditional molecular biology approaches.

While DNA sequence analysis encompasses a broad range of computational approaches in bioinformatics, from genome assembly and variant detection to evolutionary analysis and microbiome studies, this review focuses specifically on DNA sequence analysis tasks that involve pattern recognition and prediction, where artificial intelligence approaches can be effectively applied. These tasks include predicting functional elements, identifying regulatory regions, and classifying sequence types applications where AI can learn complex sequence patterns that may not be apparent through traditional computational methods.

Most of the AI-based genomics sequence analysis methods fall under the hood of regression and classification paradigms (9–11). Figure 1 illustrates a unified workflow of AI-based predictive pipelines for genomics sequence analysis tasks. It is evident in the Figure that, overall, AI predictive pipelines can be divided into 4 different stages (12). First stage emphasizes on the collection and development of quality benchmark datasets using public databases (13). Second stage focuses on the characterization of raw DNA sequences in terms of statistical vectors using different kinds of sequence encoders (14–16). This is primarily done to address the inherent dependency of AI predictive pipelines on statistical vectors (17–19). In entire predictive pipeline, this stage is the most crucial one because highly informative and discriminative statistical vectors help the predictors to learn comprehensive useful patterns for accurate prediction (14–16). It is widely accepted that with quality statistical vectors, even simple machine learning predictors can produce promising performance. On contrary, with less informative and discriminative statistical representations, even sophisticated deep learning predictors fail to produce decent performance (17–19).

There is a marathon of developing powerful sequence encoders for generating highly informative and discriminative statistical vectors of raw sequences. To date, hundreds of sequence encoding methods have been developed (12) that can be broadly classified into four categories: Physico-chemical properties based methods, statistical methods (12, 20), neural word embedding methods (21), and language models (22). While physico-chemical properties based methods generate statistical vectors of raw sequences using pre-computed physical and chemical values of nucleotides, statistical methods rely on occurrence frequencies of individual or group of nucleotides with DNA sequences (12). Physico-chemical properties based and statistical methods capture the intrinsic characteristics of biological sequences, such as nucleotide composition and distributional information. However, these methods lack to capture complex relationships of nucleotides such as long range interactions of nucleotides in the sequences (12, 23). In addition, these methods may not fully capture the semantic and functional similarities between sequences (12, 23). Neural word embedding methods learn distributed representations of nucleotides in the continuous vector space. These methods capture the syntactic and semantic similarities of nucleotides by mapping them to vectors in a high-dimensional space. This enables the representation of residues with similar contexts to be closer together in the vector space. Neural word embeddings methods efficiently capture semantic and contextual information of nucleotides. However, these methods lack to efficiently handle different contexts of same nucleotides (21). Language models also learn representation of individual nucleotides or groups of nucleotides (k-mers) in an unsupervised fashion by predicting masked nucleotides based on the context of surrounding nucleotides. Language models based methods capture complex nucleotide relations; however, these methods require large amount of sequence data for training and hyperparameter optimization (22).

Third stage includes predictors that make best use of statistical vectors produced by second stage to extract informative patterns for creating decision boundaries. Overall, these predictors can be classified into two categories: machine learning and deep learning (12). Machine learning predictors require less data and computational power for training. However, these predictors lack to capture comprehensive complex relationships of nucleotide (12), whereas deep learning predictors (24) are capable to learn highly complex relationships of nucleotide. However, these predictors require a huge amount of training data and computational power (12). In fourth stage, comprehensive evaluation of predictors using different experimental settings and evaluation measures is performed (24).

AI researchers have been endeavoring to complement wet-lab-based DNA sequence analysis methods by incorporating more innovative sequence encoders at second stage and predictors at third stage of predictive pipeline. However, there is still ample room for the development of more powerful predictive pipelines. Different fields such as Natural Language Processing (NLP), Energy, and Computer Vision have seen substantial progress in the development of diverse predictive pipelines. Whereas, the DNA sequence analysis field is known for its wide range of tasks, still the progress of AI applications in this area is hindered mainly due to the lack of integration between molecular biologist and AI experts. For instance, the field of NLP has made strides with multi-task learning predictors. However, the DNA sequence analysis field lags behind due to AI experts limited understanding of the diverse range of DNA analysis tasks that could support the development of multi-task learning predictors. Furthermore, the efficacy of AI applications hinges on the availability of benchmark datasets. Although developing datasets in DNA sequence analysis is relatively straightforward due to abundance of public databases which contain raw biological sequences along with associated labels, there is a tendency among researchers to overlook existing benchmark datasets, develop new benchmark datasets, and neglect comprehensive performance comparisons with existing predictors. This oversight often complicates the determination of the most effective predictors for specific tasks. For example, up to date, according to our best of knowledge, approximately 127 predictive models have been developed and published in 59 different conferences and journals for widely studied 44 different DNA sequence analysis tasks. To enhance the performance of predictive models developed for diverse DNA sequence analysis tasks, researchers need to conduct a comprehensive examination of existing literature to find most effective algorithms for different stages of new predictive pipelines. With an aim to expedite progress in the development of fair and robust AI applications for DNA sequence analysis, numerous review articles have emerged. However, these reviews typically focus on isolated tasks rather than providing a holistic overview. Considering the need and significance of a comprehensive study that bridges the gap between AI specialists and biologists, this paper makes manifold contributions:

It is important to note that our categorization of 44 DNA sequence analysis tasks emerges from the AI and computational biology literature rather than representing a definitive biological taxonomy. We have organized these tasks into biologically relevant groupings based on their functional and analytical similarities, while recognizing that many tasks span multiple biological domains. This organization aims to bridge the gap between computational methodologies and biological applications, although we acknowledge that future refinements with deeper domain expert input would further enhance this framework.

This section provides a detailed overview of the research methodology used to identify articles focused on word embeddings and large language models applications in DNA sequence analysis landscape (10, 11). Figure 2 illustrates two stage processes for article identification and selection.

With an aim to find molecular basis of diseases initiation and progression, their effective detection at early stages, and development of potent drugs, researchers are trying to understand DNA sequence language by performing a variety of sequence analysis tasks. Every unique DNA sequence analysis task aims to enhance the understanding of one specific aspect of DNA, and a bunch of tasks can enhance the understanding of specific major biological goal. To summarize the biological background of 44 distinct DNA sequence analysis tasks, we have categorized them into 8 major biological goals. Figure 3 depicts the biological categorization of 44 unique DNA sequences analysis tasks into 8 different goals, namely, genome structure and stability, gene expression regulation, gene analysis, gene network analysis, DNA modification prediction, DNA functional analysis, environmental and microbial genomics, and disease analysis. This biologically informed organization was developed by analyzing both the computational biology literature and aligning with biological processes in genomics research. While computational researchers often approach these tasks through the lens of AI methodologies, we have endeavored to categorize them according to their biological relevance and function. Our categorization into 8 major biological goals represents an attempt to bridge computational approaches with biological understanding. Although we recognize the inherent complexity and interconnectedness of biological systems which indicates that many tasks could reasonably be classified in multiple categories, thus, this categorization represents one of several possible ways to organize these tasks. This categorization reflects the diverse biological applications where AI-based sequence analysis has made significant contributions. However, we recognize that DNA sequence analysis in bioinformatics extends beyond these pattern recognition tasks to include other critical applications such as genome assembly, variant detection, and population genetics studies. We specifically examine how modern AI approaches are transforming our ability to extract meaningful biological insights from sequence data through pattern-based prediction tasks.

In living organisms, DNA is packaged at multiple levels to condense vast genetic information into a well-organized structure within the cell nucleus (1). At the first level, DNA is wrapped around histone octamers also known as nucleosomes. These nucleosomes further assemble into chromatin, which then folds and condenses into an even more compact structure known as the genome (1). The exploration of genome structure and stability is pivotal in understanding the biological intricacies and potential therapeutic avenues. Genome structure can affect how genes are accessed and used. Disruptions in this structure, such as missing or misplaced DNA sections, or changes in how tightly DNA is wrapped around histone octamers, or irregularities in nucleosomes positions can lead to genes being turned on or off at the wrong times or in the wrong amounts (1). This can cause various diseases and biological disorders. DNA is an instruction manual that controls biological functioning within living organisms. If genome gets unstable, the manual gets messed up such as typos and missing sections. It can lead to uncontrolled growth of the cells (cancer) and improper working of the genes (many diseases) (1). In a nutshell, a stable genome possesses clear, complete instruction manual, essential for keeping biological functions working smooth. To better understand genome structure and stability, it is essential to explore various tasks such as DNA Replication Origins Prediction (25, 26), Genome Structure Analysis (27, 28), Nucleosome Position Detection (29, 30), Chromatin Accessibility Prediction (31–33), Chromatin Feature Prediction (31, 34, 35), Long-range Chromatin Interaction Prediction (36, 37), and YY1-Mediated Chromatin Loops Prediction (38, 39). These tasks are crucial for comprehending the intricate mechanisms governing genetic information processing and regulation within cells (40).

DNA replication origin prediction is fundamental as accurate replication of the genome is vital for maintaining genomic stability (25). The prediction of replication origins involves calculating DNA structural properties to identify sites crucial for initiating DNA replication (25). Understanding where these sites are located and how they are specified is essential for comprehending DNA replication and ensuring genome integrity (41). Genome structure analysis plays a pivotal role in deciphering the organization and arrangement of genetic material within the cell (27). By analyzing the structural features of the genome, researchers can gain insights into the functional and spatial organization of chromosomes, aiding in the identification of genomic elements involved in gene regulation and phenotypic variations (27, 42). Furthermore, nucleosome position detection is essential for understanding how nucleosomes, the basic units of genome, are arranged along the DNA strand (29, 43). This information is crucial for elucidating gene regulation mechanisms and chromatin dynamics within the cell (29, 43). Chromatin accessibility prediction is a key task that involves determining the regions of chromatin that are accessible for transcription factors and other regulatory proteins to bind (31–33). Prediction of chromatin accessibility across different cellular contexts provides valuable insights into gene regulation and chromatin dynamics (31–33). Chromatin feature prediction complements accessibility prediction by identifying specific chromatin features and epigenetic markers that influence gene expression and regulatory processes (31, 34, 35, 44). These features include transcription factor (TF) binding sites, DNase I-hypersensitive sites (DHS), and histone marks (HM). By understanding these features, researchers can unravel the mechanisms underlying chromatin regulation and gene expression (34). Long-range chromatin interactions make bridges between distant enhancers and promoters. These interactions enable interactions between enhancers and promoters by bringing them closer to each other (36, 37). YY1-mediated chromatin loop prediction provides comprehensive understanding about gene regulation (38, 39, 45). YY1 is a protein that makes loop between enhancers and promoters. These loops are essential for gene regulation, and by predicting these loops, we can see which genes can be controlled through YY1 protein (38, 39, 45). This knowledge is valuable for understanding diseases where gene regulation goes wrong. To sum up, only through multi-dimensional exploration of genome structure and stability, researchers can discriminate healthy cellular processes from malfunctioned processes, find the root causes of diseases, and develop potent therapies.

Another major goal of molecular biologists behind is gene expression regulation. Gene expression regulation provides fundamental insights into how genes are activated or repressed in response to various cellular cues (46). Specifically, researchers are trying to unravel the intricate mechanisms that control when and up to what extent specific genes are turned on or off in different cells and tissues (46). This knowledge forms the basis for understanding the functional behavior of genes in different biological contexts and sets the stage for further analyses. Hence, it holds immense promise for scientists and pharmaceutical industries. This helps scientists to detect irregularities in normal gene expression regulation, the way diseases develop at the molecular level, and identify potential drug targets (46). Furthermore, this understanding can assist pharmaceutical industries to develop improved diagnostic tools, innovative personalized therapies, and targeted interventions, which will ultimately contribute to advancements in personalized healthcare (46). In addition, it can provide a deeper understanding of biological systems which can lead to breakthroughs in biotechnology (46). For better understanding of gene expression regulation, researchers are performing nine different DNA sequence analysis tasks, namely, enhancer identification (47), promoter identification (48), enhancer-promoter interactions prediction (49), transcription site prediction (50), transcription factor binding site prediction (51), transcription factor binding affinity prediction (52), protein-DNA binding site prediction (53), splice site prediction (53), and translation initiation site prediction (54). Enhancers (47, 55–75) and promoters identification (48, 76–81), along with their interactions (82–86) prediction are important to decipher a complex control panel for gene expression (47–49). Enhancers are known as distant switches of genes, while promoters are the landing sites where gene activation starts. Identification of these elements and predicting how they loop together provide a comprehensive understanding of gene regulation, including which genes are activated or repressed, the intensity of their expression, and the specific cell types involved (87, 88). This knowledge reveals the intricate regulatory code that governs gene expression and offers valuable insights into the mechanisms underlying normal cellular function as well as the dysregulation that may contribute to various diseases.

Furthermore, prediction of different genomic sites including transcription sites (50), transcription factor binding sites (89–93), transcription factor binding site affinity (52), protein-DNA binding site (53, 94–96), splice site (93, 97–100), and translation initiation site (50, 101) provide deep insights into gene expression regulation. A transcription site refers to the specific location on the DNA where the process of transcription takes place. Transcription is the synthesis of RNA from a DNA template, and the transcription site represents the region where the RNA polymerase enzyme binds and initiates the transcription process, whereas transcription factor binding sites are specific DNA sequences where transcription factors (proteins), that regulate gene expression, bind. These binding sites are typically located near the transcription start site and are recognized by transcription factors to control the initiation or repression of transcription. In contrast, transcription factor binding site affinity refers to the strength or affinity with which a transcription factor binds to its specific binding site on DNA. It represents the likelihood of a transcription factor binding to its target site and influencing gene expression. A protein-DNA binding site refers to any region on the DNA where a protein binds. This can include transcription factors, as mentioned earlier, as well as other proteins involved in various cellular processes such as DNA replication, repair, and chromatin remodeling. Splice sites are specific sequences within a gene's DNA that mark the boundaries of introns and exons. During the process of RNA splicing, introns are removed from the pre-mRNA molecule, and exons are joined together to form the mature mRNA. Splice sites are essential for the accurate and precise splicing of RNA. Translation initiation site (TIS) is the specific location on the mRNA molecule where the process of translation begins. TIS prediction seems like a RNA sequence analysis task; however, in molecular biology research, to study gene expression, researchers are synthesizing complementary DNA (cDNA) data from messenger RNA (mRNA) template through a process called reverse transcription. In the context of cDNA data, the translation initiation site (TIS) represents the position where the ribosome, the cellular machinery responsible for protein synthesis, binds to the mRNA to initiate translation. The TIS is typically identified by the presence of specific start codons, such as AUG, which serve as signals for the ribosome to start protein synthesis.

To better understand gene functions and their roles in disease initiation, researchers are exploring various aspects such as gene expression prediction (102, 103), identification of essential (104–109) and disease-specific genes (110), gene function prediction (111, 112), pseudo-gene function prediction (111), target gene classification (113), and candidate gene prioritization (114). Overall together, these tasks provide a comprehensive platform for disease diagnosis and development of treatment strategies by uncovering disease mechanisms, identifying potential therapeutic targets, and organizing genes into functional categories. Specifically, gene expression prediction provides useful information about the level of gene activity in different cells or tissues (115). This task is vital for understanding the molecular mechanisms underlying complex diseases such as cancer and identifying potential therapeutic targets. Essential gene identification is another critical task in gene analysis that helps researchers pinpoint genes that are crucial for an organism's survival and development (116, 117). This task is particularly important in understanding gene function and the genetic basis of various disorders. Gene function prediction elucidates the roles of genes in different pathways and biological processes and provides valuable insights into disease mechanisms and potential therapeutic interventions.

Apart from gene function prediction, pseudo-gene function prediction has gained a lot of attention as a critical task in gene analysis (111). Pseudogenes were once thought to be useless DNA because they cannot code for proteins due to mutations that happened over time. However, recent studies have shown that pseudogenes actually play important roles in controlling genes, especially in cancer. For instance, the pseudogene PTENP1 helps to regulate the tumor suppressor gene PTEN in various cancer conditions, showing that pseudogenes can have important functions. Pseudogene function prediction offers numerous advantages, including better understanding of gene regulation, disease mechanisms, evolutionary biology, and the potential for new biomarkers and drug targets. In addition, disease gene prediction is a pivotal task in gene analysis that focuses on identifying genes associated with specific diseases or disorders (118). By pinpointing disease-related genes, researchers can unravel the genetic basis of diseases, discover novel biomarkers for diagnosis and prognosis, and develop targeted therapies. This task is instrumental in precision medicine approaches, where understanding the genetic underpinnings of diseases is crucial for personalized treatment strategies. Target gene classification involves categorizing genes based on their functions, interactions, or regulatory mechanisms (119). By classifying target genes, researchers can better understand gene networks, signaling pathways, and biological processes. This task is essential for deciphering the complex relationships between genes and their roles in health and disease. Candidate gene prioritization and selection are critical tasks in gene analysis that aim to identify genes with the highest likelihood of being involved in a particular biological process or disease (120). By prioritizing candidate genes, researchers can focus their efforts on studying genes that are most likely to have significant effects, accelerating the discovery of novel gene functions and disease mechanisms. This task is crucial for efficiently allocating research resources and maximizing the impact of genetic studies. Aforementioned seven DNA sequence analysis tasks are essential for advancing our understanding of genes and their roles in health and disease. By leveraging these tasks, researchers can unravel the complexities of the genome, uncover novel gene functions, and pave the way for innovative diagnostic and therapeutic strategies in various fields of biology and medicine.

Furthermore, gene network analysis is a promising goal that seeks to comprehend the intricate interactions and relationships between genes within a biological system. Two primary tasks within Gene Network Analysis are Gene Taxonomy Classification and Gene Network Reconstruction. Gene Taxonomy Classification (121–123) involves categorizing genes based on their evolutionary relationships and functional similarities, providing a structured framework for organizing genetic information. Gene Taxonomy Classification plays a crucial role in gene network analysis by offering a foundational structure for understanding the evolutionary history and functional relationships between genes. By classifying genes into taxonomic groups based on shared characteristics and evolutionary relatedness, researchers can infer valuable insights into the origins and evolutionary trajectories of genes within a network (124). This classification allows for the identification of core genes that have remained conserved throughout evolution, providing a basis for inferring phylogenetic relationships and understanding the fundamental building blocks of gene networks. Moreover, Gene Taxonomy Classification enables researchers to utilize existing knowledge about gene functions and evolutionary relationships to guide Gene Network Reconstruction. By categorizing genes into taxonomic groups, researchers can pinpoint gene clusters with similar functions or evolutionary origins, facilitating the identification of modules within gene networks that exhibit coordinated activity (125). This classification serves as a roadmap for exploring the functional roles of genes within a network and understanding how these roles have evolved over time. On the other hand, Gene Network Reconstruction (126–128) involves creating a detailed map of the interactions and regulatory relationships between genes within a cell or an organism. The primary input for gene network reconstruction is gene expression data obtained through high-throughput techniques such as RNA sequencing (RNA-seq) or microarrays. This task is pivotal for understanding how genes work together to control various biological functions and processes (129). By reconstructing gene networks, researchers can uncover key regulatory hubs involving highly connected genes, clusters of closely interacting genes, pathways, and interactions that steer cellular functions and responses to external stimuli (130).

DNA modification prediction is also a crucial goal where researchers aim is to decipher how tiny tweaks to the DNA code can lead to big changes in cellular functions (131–133). In DNA modifications, distinct chemical groups are added to specific locations on the DNA molecule. These additions do not change the actual sequence of nucleotides (A, C, G, T) but can alter the physical properties of DNA sequence. Understanding these modifications, such as 4-Methylcytosine (4mc) (134–143), Methyladenine (6ma) (144–151), 5-methylcytosine (5mc) (152, 153), 5-hydroxymethylcytosine (5hmc) (154–157), and methylation modifications (146, 154–159), are essential for advancing our comprehension of epigenetic regulation (160–162). Specifically, methylation modifications that occur due to the addition of methyl groups to DNA molecules play a pivotal role in regulating gene expression and maintaining genomic integrity. Similarly, methyladenine modifications, such as DNA N6-methyladenine (6mA), occur due to the addition of a methyl group to the adenine base of DNA. DNA 6mA modifications dynamically influence DNA thermal stability, curvature, and transcription factor interactions, impacting gene expression in a heritable manner. Understanding the prediction of 6mA sites is pivotal for both basic and clinical research as it aids in the identification of gene expression patterns and potential epigenetic changes induced by environmental factors. These predictions enhance our ability to study the role of 6mA modifications in diseases and could lead to improved therapeutic strategies, highlighting the relevance of accurate prediction methods in unraveling the complexities of DNA modifications. Moreover, 5-methylcytosine (5mc) modification occurs due to the addition of a methyl group to the cytosine base of DNA, whereas 5-hydroxymethylcytosine (5hmc) modification is an oxidized derivative of 5mc, where an additional hydroxyl group (-OH) is added to the methyl group of 5mc. Prediction of 5-methylcytosine (5mc) and 5-hydroxymethylcytosine (5hmc) modifications is essential for decoding their roles in gene regulation, developmental processes, and disease states. These critical epigenetic modifications are dynamically regulated by enzymes and influence gene expression crucial for neuronal differentiation and cellular proliferation. Abnormal levels of these modifications have been linked to diseases such as cancer. Precise prediction of 5mc and 5hmc sites is useful for the development of targeted therapies and improved prognostic assessments.

Functional genomics is also a critical goal that encompasses multiple sub-tasks including species classification (44), conserved non-coding element (NCE) classification (163), functional prioritization of non-coding variants (34), prediction of context specific functional impact of genetic variants (36), exon and intron region classification (164), and recombination spots identification (165). Each of these tasks plays a vital role in unraveling the complexities of genetic regulation and molecular mechanisms within the genome. In biomedical research, understanding the genetic similarities and differences between humans and other species is crucial for modeling diseases and studying genetic disorders. Majority of the genome is conserved across different species which makes it difficult to distinguish humans and non-human species. Despite very high genetic similarity across species (< 10% sequence divergence), small differences are extremely valuable and they have significant biological implications. Species classification determines the source species of genetic sequences based on such differences and pave way for better modeling diseases and studying genetic disorders (44). Conserved non-coding element classification is another critical task in functional genomics that focuses on identifying and understanding non-coding regions of the genome that are evolutionarily conserved across different species (163). It is essential for advancing our understanding of gene regulation, evolutionary biology, and the genetic basis of diseases. By elucidating the functions of these non-coding regions, researchers can gain insights into the intricate regulatory networks that govern gene expression and cellular processes and contribute to the development of targeted therapies.

Functional prioritization of non-coding variants (34) is another crucial task for making sense of the vast amount of genetic data generated by modern sequencing technologies. By identifying which variants have significant biological impacts, researchers can gain a deeper understanding of the genetic architecture of complex diseases, uncover novel therapeutic targets, and advance the field of precision medicine. This prioritization is essential for translating genomic research into practical health benefits and ultimately improving patient outcomes and advancing our knowledge of human biology (34). As functional prioritization of non-coding variants task involves identifying which non-coding variants among millions are likely to have functional consequences, it does not account for the specific context in which these variants might exert their effects, whereas prediction of context-specific functional impact of genetic variants aims to provide a detailed understanding of how specific variants influence gene function in different contexts (e.g., specific tissue) (36). This is particularly important for genetic studies that seek to uncover the mechanisms by which variants contribute to disease phenotypes. Unlike functional prioritization of non-coding variants task which only filters the variants that are most likely to have functional significance. Prediction of context-specific functional impact of genetic variants provides a finer level of detail by predicting the actual effect of a variant on gene expression or other functional outcomes in specific tissues. This granularity is essential for precisely understanding the specific biological mechanisms and for developing targeted therapies (36).

Exon and intron region classification is crucial for understanding gene structure and function within the genome. Exons are coding regions that are translated into proteins, while introns are non-coding regions that are spliced out during mRNA processing. By classifying exons and introns, researchers can describe gene boundaries, identify functional elements, and elucidate the mechanisms of gene expression regulation (166). This task is essential for deciphering the genetic code and unraveling the complexities of gene regulation in health and disease. Recombination spots identification is a pivotal task in functional genomics that focuses on mapping regions of the genome where genetic recombination events occur. Genetic recombination is a natural process where DNA segments are exchanged between two chromosomes during cell division. Recombination plays a vital role in generating genetic diversity, ensuring proper chromosome segregation, and driving evolution (167). By identifying recombination hot spots, researchers can gain insights into the mechanisms underlying genetic diversity and genome evolution, shedding light on the processes that shape genetic variation and adaptation in populations. In conclusion, the tasks related to functional genomics, including species classification, conserved non-coding element classification, functional prioritization of non-coding variant, prediction of context-specific functional impact of genetic variants, exon and intron region classification, and recombination spots identification, are essential for advancing our understanding of genetic regulation, molecular mechanisms, and disease pathogenesis. By delving into these tasks, researchers can unravel the complexities of the genome, decipher the genetic basis of diseases, and pave the way for precision medicine and personalized healthcare interventions tailored to an individual's genetic profile.

Another goal of researchers is to study overlap between two distinct fields namely environmental science and microbial genomics (27). This interdisciplinary study enables researchers to explore how environmental factors such as pollution, climate change, and agricultural practices affect on function and diversity of microbial communities (27). A key area of focus in this field is the nitrogen cycle prediction. By examining the genomes of microbes involved in nitrogen fixation, nitrification, and denitrification, scientists can predict how these processes might respond to environmental changes (168). This prediction provides understanding about potential impacts of environmental shifts on ecosystem health (169) and nitrogen availability, which are essential for plant growth and overall biogeochemical cycles (170).

From all eight different biological goals, disease analysis goal has received huge attention in scientific community as it aims to understand, diagnose, and treat various illnesses. Within this field, several tasks play a vital role in enhancing our comprehension of diseases. One such task is Pathogen Signatures Identification (171), which involves identifying specific markers or characteristics of pathogens that can aid in their detection and classification (172). By pinpointing these signatures, researchers can develop targeted diagnostic tools and therapies, ultimately improving disease management and control. Mutation Susceptibility Analysis (173) is another essential task in disease analysis. This task focuses on investigating the genetic variations that make individuals more prone to developing certain diseases (174). Understanding mutation susceptibility can aid in personalized medicine approaches, where individuals at higher risk can be identified early for preventive interventions or closer monitoring. Phage-Host Interactions Prediction (175–177) is a task that delves into the relationships between bacteriophages and their host bacteria (178). By predicting these interactions, researchers can gain insights into how phages influence bacterial populations, which is crucial for developing phage-based therapies to combat bacterial infections and antibiotic resistance. Disease Risks Estimation (90) is a fundamental aspect of disease analysis that involves assessing the likelihood of an individual developing a particular condition based on various factors such as genetics, lifestyle, and environmental exposures (179). Accurately estimating disease risks enables healthcare providers to offer targeted interventions and counseling to high-risk individuals, potentially preventing the onset or progression of diseases. Tumor Type Prediction (180) is a significant task in disease analysis that focuses on identifying the specific type of tumor a patient may have based on various characteristics such as genetic markers, imaging features, and histopathological findings (181). Predicting tumor types is essential for determining the most effective treatment strategies and prognostic outcomes for patients with cancer. Pathogenicity Potential Assessment (27) is a critical task that involves evaluating the ability of pathogens to cause disease in a host. By assessing the pathogenicity potential of different microorganisms, researchers can prioritize the development of interventions against the most virulent pathogens, thereby improving disease prevention and control strategies. Phylogenetic Analysis (21) is a key component of disease analysis that involves studying the evolutionary relationships between different strains of pathogens or tumor cells. Phylogenetic analysis provides insights into the origins, spread, and diversification of diseases, aiding in the development of targeted interventions and understanding disease transmission dynamics.

While Section 3 presents a biologically motivated categorization of DNA sequence analysis tasks, this section reframes these same tasks from a computational perspective. This dual categorization approach (biological and computational) aims to facilitate interdisciplinary understanding between life scientists and AI researchers. With the influx of biological data and rise of AI, researchers are increasingly applying AI in diverse areas of molecular biology. Development of large scale AI applications requires a good understanding of variety of sequence analysis tasks. However, there exist a huge domain gap between computer scientists and molecular biologists. Molecular biologists know the need, biological importance, and pharmaceutical worth of different sequence analysis tasks. However, they do not know which machine or deep learning models are most appropriate to use to either replace or complement experimental work. Similarly, computer scientists know which Artificial Intelligence predictive pipeline can potentially perform better with specific type of data; however, they do not know the nature of biological sequence analysis tasks. For instance, DNA sequence analysis tasks such as gene function prediction, gene network reconstruction, gene expression prediction, and disease risk estimation can be challenging for computer scientists to grasp. However, a comprehensive literature review that explains the basics of these tasks can bridge this gap. For example, gene function prediction is a multi-label classification tasks, gene expression prediction is a regression task, while gene network reconstruction and disease risk estimation are binary classification tasks. With this foundational understanding, computer scientists can more easily develop predictive pipelines for these binary, multi-label classification, and regression tasks. To empower AI experts, we have presented 44 DNA sequence analysis tasks in computer scientist language in Figure 4. A simple look on Figure 4 reveals that nature of DNA sequence analysis tasks can be categorized into three primary types: regression, clustering, and classification where classification can be further divided into three secondary types: binary classification, multi-class classification, and multi-label classification. Let us mathematically formulate the possible natures of DNA sequence analysis tasks.

In binary classification, researchers aim to predict the outcome of a binary variable (0 or 1). Given a dataset with features X ∈ ℝ^nxd, binary labels y ∈ 0, 1, and training dataset (x₁, y₁), (x₂, y₂), …, our goal is to learn a decision function f:X → Y that maps inputs to binary outputs 0, 1 on the basis of hypothesis function h(x) learned from the training data.

In multi-class classification, researchers aim to predict the outcome from more than two classes. Specifically, given a dataset having sequences X ∈ ℝ^nxd, labels y ∈ 1, 2, …, K where K is the number of classes, and training dataset (x₁, y₁), (x₂, y₂), …, (x_n, y_n) where x_i ∈ X and y_i ∈ Y, our goal is to learn a decision function f:X→Y that assigns inputs to one of the classes.

where h_k(x) is the hypothesis function for class k learned from the training data. On the other hand, in multi-label classification, each input can be assigned to multiple classes simultaneously. Given a dataset with features X ∈ ℝ^nxd, labels y ∈ 1, 2, …, K where K is the number of classes, and training dataset (x₁, y₁, y₂, ..), (x₂, y₁, y₄, …), …, (x_n, y5, y_n, ….) where x_i ∈ X and y_i ∈ Y, our goal is to learn a decision function f:X → 0, 1^K that assigns inputs to multiple classes simultaneously using hypothesis function h_k(x) for class k learned from the training data.

Furthermore, in regression, researchers goal is to predict a continuous outcome variable. Given a dataset with sequences X ∈ ℝ^nxd, labels y ∈ ℝ, and training dataset (x₁, y₁), (x₂, y₂), …, (x_n, y_n) where x_i ∈ X and y_i ∈ Y, our goal is to learn a function f:X → ℝ that predicts continuous outputs using hypothesis function h(x) learned from the training data.

In clustering, the goal is to group similar data points into same clusters. Given a dataset with data points X = x₁, x₂, …, x_n, where each xi∈ℝd, our goal is to find a partition of the data into clusters C = C₁, C₂, …, C_K. This is done on the basis of a distance metric d(x, μ_c) between data point x and the centroid μ_c of cluster c.

This section provides a comprehensive overview of various databases employed to develop benchmark datasets for development of AI-based applications for 44 distinct DNA sequence analysis tasks. A total of 45 DNA sequence databases have been identified from 127 existing studies. Among these, 36 databases are publicly accessible, while the remaining 9 databases are either inaccessible or no longer exist. To ease the lives of researchers and practitioners, Table 1 summarizes accessible databases in terms of their release year, types of inherent genetic data (DNA, RNA, protein), details of species and organisms, statistics of raw sequences, and supported data formats.

A holistic view of the Table 1 reveals that 12 databases provide RNA and protein sequences as well in addition to providing DNA sequences. As word embeddings methods and large language models are trained in unsupervised fashion and when they are trained on large sequence data usually, they produce better representations. To efficiently train word embedding methods and large language models, raw data can be acquired from these databases. To facilitate researchers, we have categorized 36 databases into three different categories on the basis of volume of raw sequences: low sequence facilitators, medium sequence facilitators, and high sequence facilitators. Specifically, 13 low sequence facilitators, namely, HOCOMOCO Human v11 database (182), Consensus Coding Sequence Database (183), MSigDB (184), Broad DepMap (185), JASPAR (186), Database of Essential Genes (187), ENCODE (188), MGC (189), Exon-Intron Database (190), Ensembl (191), RegulonDB (192), EPD2 (193), offer up to 100,000 DNA sequences each, while 9 medium sequence facilitators, namely, PPD (194), DREAM (195), EmExplorer database (196), GenomAD (197), DeOri (198), BioLip (199), DeOri6.0 (198), GWAS (200), Eukaryotic Promoter Database (193), provide up to 1 million DNA sequences. In contrast, 13 high sequence facilitators such as Descartes (201), EnhancerAtlas 2.0 (202), COSMIC (203), DisGeNet (204), ClinVar (205), CCLE (206), GENCODE (207), Gene Ontology (208), DataBase of Transcriptional Start Sites (209), GEO (210), KEGG (211), NCBI (212), GenBank (213), and dbSNP (214, 215) offer more than 1 million DNA sequences each. These databases predominantly house DNA sequences from a diverse array of species, including humans, mice, plants, bacteria, and fungi. A comprehensive analysis reveals that approximately 22 databases, namely, Descartes (201), DREAM (195), EmExplorer database (196), COSMIC (203), DisGeNet (204), GenomAD (197), ClinVar (205), HOCOMOCO Human v11 database (182), DeOri (198), BioLip (199), GWAS (200), Broad DepMap (185), CCLE (206), GENCODE (207), Consensus Coding Sequence Database (183), MSigDB (184), ENCODE (188), DataBase of Transcriptional Start Sites (209), MGC (189), GEO (210), Ensembl (191), and OMIM (216), focus on animal DNA sequences, 4 databases including PPD (194), Database of Essential Genes (187), RegulonDB and (192) on bacterial sequences, and JASPAR (186) on plant DNA sequences. EnhancerAtlas 2.0 (202) is the only database that facilitates with both animal and bacterial DNA sequences, while 4 databases namely DeOri6.0 (198), Exon-Intron Database (190), EPD2 (193), and Eukaryotic Promoter Database (193) focus on animal and plant DNA sequences, whereas Gene Ontology (208), KEGG (211), and GenBank (213) provide DNA sequences for animal, plant, and bacteria. In addition, sequences from other organisms such as eukaryotes, invertebrates, fungi, and various microorganisms are also well-represented. Some databases encompass a broad spectrum of species. For instance, the EDP2 (193) database includes genomics data for 139 species, GenBank (213) houses sequences for 557,000 species, and PPD (194) has genomics data of 63 species.

Moreover, Table 1 includes data formats utilized by various databases to manage and provide access to DNA sequences. TXT and FASTA format are universally accepted by almost all DNA sequence analysis programs. Each entry in both format types contains at least two lines: First line or header includes accession number, species name, or identification details, while next line contains nucleotide sequences. CSV and TSV are text-based formats in which values in rows are separated by commas or tabs, respectively. In both file formats, first row specifies headers which defines names of columns (“SeqID”, “SeqName”, “Type”, “Function”) and subsequent rows represent data. In VCF format, first row specifies headers which defines names of columns, but this format is specifically used to store genetic variation data including single nucleotide polymorphisms (SNPs), insertions, deletions, and structural variants. In addition, XLSX formats represent complex datasets that contain information computed with various formulas across multiple columns, whereas EMBL format includes structured sections for sequence data, feature annotations (genes and other biological features), organism information, references, and other details. An extensive analysis of Table 1 reveals that most widely used data formats are FASTA, TXT, CSV, XLSX, and EMBL in DNA sequence analysis.

A rigorous analysis of Table 1 reveals that out of 36 publicly accessible databases, several key categories of data emerge. Four databases, namely, Broad DepMap (185), genomAD, COSMIC, and MGC, provide data for DNA functional analysis tasks such as prediction of context-specific functional impact of genetic variants and conserved non-coding element classification. Seven databases, namely, BioLip, HOCOMOCO Human v11, GWAS, EnhancerAtlas 2.0, DataBase of Transcriptional Start Sites, Exon-Intron Database, and Eukaryotic Promoter Database, offer data on gene expression regulation. Three databases, namely, PPD, CCLE, and EmExplorer, focus on DNA modification data including methylcytosine and methyladenine modifications. In addition, DeOri, Descartes, DeOri6.0, and JASPAR provide information on gene structure and stability, including chromatin accessibility prediction, YY1-mediated chromatin loop identification, and DNA replication origins identification. GENCODE, Consensus Coding Sequence Database, MSigDB, Gene Ontology, DisGeNet, Database of Essential Genes, KEGG, and NCBI offer comprehensive gene analysis data. Furthermore, eight other databases, namely, EPD, ENCODE, RegulonDB, GEO, Ensembl, ClinVar, GenBank, and OMIM, provide a range of data on gene expression regulation, DNA modification prediction, genome structure and stability, DNA functional analysis, disease information, and gene analysis.

The quality and quantity of datasets utilized in AI-driven DNA sequence analysis applications are vital determinants of their effectiveness and functionality. This section aims to provide a comprehensive overview of datasets relevant to 44 distinct DNA sequence analysis tasks. Overall, these datasets fall into two primary categories: publicly available datasets and in-house datasets. This categorization serves to illuminate the significance of dataset accessibility and its implications for the advancement of AI-driven DNA sequence analysis. Specifically, publicly available datasets are accessible to the wider research community and are commonly employed in the development of AI-based predictive models. They serve as foundational resources that facilitate the advancement of AI-driven DNA sequence analysis pipelines by ensuring accessibility, reusability, and transparency in research endeavors. Furthermore, the utilization of publicly available datasets fosters collaboration and knowledge exchange within the scientific community, thereby contributing to the overall progress of the field. In contrast, in-house datasets are proprietary in nature and are developed within specific research laboratories or institutions. These datasets often contain sensitive data tailored to particular research objectives. As in-house datasets cannot be shared publicly, their proprietary nature may limit broader access, reproducibility, and applicability of findings.

Rigorous assessment of 127 existing studies reveals that a total of 242 benchmark datasets related to 44 distinct DNA sequence analysis tasks are constructed or acquired from existing literature. Specifically, among these 242 benchmark datasets, 199 are publicly available and 43 are in-house datasets. Table 2 provides the distribution of public and in-house datasets for 44 distinct DNA sequence analysis tasks. It provides information about which of these datasets are used by word embeddings, large language models, nucleotide composition, and positional information-based predictive pipelines.

For each DNA sequences analysis task, public and in-house datasets are distributed as DNA Replication Origins Identification (0, 5), Nucleosome Position Detection (11, 0), Chromatin Accessibility Prediction (2, 0), YY1-Mediated Chromatin Loop Prediction (4, 0), Genome structure analysis (0, 1), Chromatin Feature Prediction (3, 0), Long-range chromatin interaction prediction (1, 0), Enhancers Identification (12, 0), Promoter Identification (15, 0), Enhancer-Promoter Interactions Prediction (18, 2), Transcription Site Prediction (1, 0), Transcription Factor Binding Site Prediction (4, 4), Transcription Factor Binding Affinity Prediction (2, 0), Protein-DNA Binding Site Prediction (5, 0), Splice Site Prediction (10, 0), Translation Initiation Sites (1, 1), Essential Gene Identification (6, 5), Disease Gene Prediction (1, 0), Pseudogene Function Prediction (3, 0), Target Gene Classification (1, 0), Candidate Gene Prioritization/ Identification (0, 1), Gene Function Prediction (4, 0), Gene Expression Prediction (4, 0), Gene Taxonomy Classification (2, 1), Gene Network Reconstruction (2, 6), 4mc-Methylcytosine Site Prediction (16, 0), 6mA-Methyladenine Site Prediction (5, 0), 5mc-Methylcytosine Site Prediction (24, 1), 5hmc-Methylcytosine Site Prediction (2, 0), Methylation Site Prediction (17, 0), Conserved Non-Coding Elements Classification (0, 1), Functional Priorizitation of non-coding variants (3, 0), Exon and Intron Region Classification (0, 1), Recombination Spots Identification (1, 0), Species Classification (8, 0), Prediction of context-specific functional impact of genetic variant (1, 0), Nitrogen Cycle Prediction (0, 1), Pathogen Signatures Identification (0, 1), Phage-Host Interactions Prediction (8, 0), Mutation Susceptibility Analysis (0, 2), Tumor Type Prediction (1, 0), Pathogenicity Potential Assessment (0, 8), Phylogenetic Analysis (0, 1), and Disease Risks Estimation (2, 0). First entry in brackets refers to count of public datasets, and second entry indicates total number of in-house datasets for a particular task. For example, in “Essential Gene Identification (6, 5)” task, 6 refers to public datasets while 5 represents in-house datasets.

A holistic view of Table 2 reveals 110 public and 18 in-house datasets are employed to develop both word embeddings and language models based predictive pipelines for 12 DNA sequence analysis tasks, namely, DNA replication origins identification, enhancers identification, promoters identification, enhancer-promoter interaction prediction, transcription factor binding site prediction, essential gene identification, gene function prediction, gene expression prediction, gene taxonomy classification, 4mC-methyl cytosine modification prediction, 5mC-methl cytosine modification, and 6mA-methyl modification prediction. Notably, both types of predictive pipelines have utilized 1 common dataset to evaluate the performance of predictive models developed for three tasks, namely, enhancer identification, essential gene identification, and 5mC-methyl cytosine modification prediction.

Furthermore, 112 public and 15 in-house datasets are used to develop both word embedding and nucleotide compositional and positional information-based predictive pipelines for 11 DNA sequence analysis tasks including essential gene identification, gene network reconstruction, 4mC-methyl cytosine modification prediction, 5mC-modification prediction, 6mA-methyl adenine modification prediction, and phage-host interaction prediction. However, both predictive pipelines have used 9 common pubic dataset for only three tasks. Specifically, six public datasets for enhancer-promoter interactions prediction, one public data for essential gene identification, and two public datasets for 4mC-Methyl cytosine modification prediction are commonly employed by both predictive pipelines.

Moreover, Table 2 highlights that 107 public and 9 in-house datasets are utilized by 9 DNA sequence analysis tasks, namely, enhancers identification, promoters identification, enhancer-promoter interaction prediction, splice site prediction, translation initiation sites identification, essential gene identification, 4mC-methyl cytosine modification prediction, 5mC-methl cytosine modification, and 6mA-methyl modification prediction for developing both language models and nucleotide compositional and positional information-based predictive pipelines. Merely, 7 public datasets are used commonly by both predictive pipelines for two tasks: one for promoter identification and six for 4mC-methyl cytosine modification prediction.

Although all three different types of representation learning-based predictive pipelines are employed across six different DNA sequence analysis tasks, namely, enhancers identification, promoters identification, enhancer-promoter interaction prediction 4mC-methyl cytosine modification prediction, 5mC-methl cytosine modification, and 6mA-methyl modification prediction, only on one task, namely, promoters identification, all three kinds of predictive pipelines are evaluated on one common dataset. These statistics reveal that researchers have focused on creating new datasets for each kind of predictive pipelines instead of using existing datasets. Consequently, this domain lacks a fair performance comparison between different kinds of predictive pipelines.

This section dives into 12 most commonly used word embedding approaches, 8 large language models, 9 machine learning, 8 deep learning, and 3 statistical algorithms that are used in development of predictive pipelines for 44 different DNA sequence analysis tasks.

AI-driven DNA sequence analysis predictive pipelines are evaluated using two different experimental settings: (1) k-fold cross-validation (48, 78) and (2) Train-test split (108, 110). In k-fold cross-validation, dataset is splitted into k folds, where k−1 folds are used for training and one fold is used for testing. In next iterations, from k-folds, another fold is reserved for testing whereas remaining k−1 folds are used for training. In this way, pipelines are trained and tested k times on whole data. This method offers more precise assessment of model generalization capability. Specifically for deep learning models (236), an additional set, known as validation set, is created from training set which typically uses 10% of training data. This validation set is used to optimize the model's hyperparameters. In train-test split experimental setting, data are divided into two distinct sets: (a) train set and (b) test set. Train set comprises majority of data (usually 70%–80%), while test set contains remaining 20%–30%. Similar to k-fold cross-validation, validation set is also created from train set for deep learning models.

Among 127 DNA sequence analysis studies, 67 studies have utilized 5-fold cross-validation-based experimental setting. Thirty five studies have used 10-fold cross-validation-based setting and 17 studies have used train test split-based setting. Eight studies have used both k-fold cross validation and train test split-based setting. Performance and effectiveness of trained predictive pipelines highly depends on ability to handles new and unseen data. To assess effectiveness and performance of predictive pipelines from different perspectives, various evaluation measures have been proposed. Based on task type, these measures are categorized into four classes: binary (92, 153)/multi-class classification (27, 173), multi-label classification (111, 112), regression (102, 103), and clustering (21). Following subsections summarize details of all four types of evaluation measures.

The public availability of predictor source codes, pretrained language models, and word embeddings significantly benefits researchers by preventing the need to reinvent the wheel. These resources enable researchers to build on existing work, utilizing pre-trained models and complete predictive pipelines to develop new, enhanced applications. By integrating new strategies into these established pipelines, they can create more powerful predictors. In addition, open-source access to these codes allows for the reproduction of predictor performance, fostering transparency and reliability in research. To expedite the establishment of more precise, robust, reliable, and efficient AI models for DNA sequence analysis and ultimately accelerate advancements in genomics and bioinformatics research, this section provides a summary of open source predictive pipelines developed using two representation learning approaches: word embeddings and large language models for 44 different DNA sequence analysis tasks.

Our analysis reveals that, out of 39 existing word embedding based DNA sequence analysis studies, only 25 studies have made the source codes of their predictive pipelines publicly accessible. In addition, source code of only 38 studies is publicly available out of 67 existing DNA sequence analysis studies based on large language models. Tables 4, 5 offer details on open-source codes for DNA sequence analysis predictive pipelines based on word embeddings and large language models, respectively. They also provide a summary of the representation learning methods and machine/deep learning predictors employed, along with links to the corresponding source codes.

A close look at Table 4 reveals that 25 AI-driven predictive pipelines are developed for 16 unique DNA sequence analysis tasks. These tasks include disease gene identification, phage-host interactions prediction, nucleosome position detection, enhancer identification, promoter identification, enhancer-promoter interactions prediction, YY1-mediated chromatin loop prediction, methylcytosine site prediction, methyladenine site prediction, essential gene identification, disease gene prediction, pseudogene function prediction, mutation susceptibility analysis, target gene classification, gene taxonomy classification, protein-DNA binding sites identification, and recombination spots identification. In addition, a high-level overview of Table 4 illustrates that a total of 2 node2vec and OPA2Vec word embedding approaches along with MLP and RF classifiers have made their source code publicly available for disease gene identification. In addition, source code of 4 Word2vec and FastText word embedding approach-based predictive pipelines is publicly available for promoter and enhancer identification tasks. Furthermore, two open-source FastText and node2vec word embedding approach-based predictive pipelines are developed for essential gene identification. Moreover, four Word2vec and one FastText word embeddings based predictive pipelines are developed for DNA methylation modification predictive pipelines.

Overall, Table 4 encompasses source codes of 7 unique word embedding approaches (Word2Vec, FastText, GloVe, Node2Vec, OPA2Vec, Graph2Vec, SDNE). Furthermore, a total of 3 machine learning classifiers, namely, RF, SVM, and XGBoost, 4 standalone deep learning classifiers, namely, MLP, CNN, GCN, and BiLSTM, and 6 hybrid deep learning models are used for the development of 26 predictive pipelines for 19 distinct DNA sequence analysis tasks.

Analysis of Table 5 demonstrates that 38 predictive pipelines are developed using 4 unique large language models, namely, BERT, ALBERT, GPT, and Transformer, and 9 unique classifiers, namely, RF, CatBoost, DF, MLP, CRF, CNN, LSTM, FGM, and hybrid (CNN, BiLSTM). Overall, these 38 large language models based predictive models are evaluated across 24 unique DNA sequence analysis tasks. These 24 tasks include chromatin accessibility prediction, species classification, protein-DNA binding site prediction, long-range chromatin interaction prediction, prediction of context-specific functional impact of genetic variants, enhancer-promoter interaction prediction, gene expression prediction, tumor type prediction, methyladenine modification prediction, methylation modification prediction, methylcytosine modification prediction, conserved non-coding element classification, nucleosome position prediction, promoter identification, splice site prediction, transcription factor binding site prediction, transcription factor binding affinity prediction, transcription site prediction, translation initiation site prediction, dna replication origin prediction, enhancer identification, gene function prediction, protein-dna interface hotspots prediction, and candidate gene prioritization and selection. A high level overview of Table 5 reveals that a total of two open-source chromatin accessibility predictive pipelines and two open-source gene expression prediction pipelines use transformers. In contrast, two open-source protein-DNA binding site identification pipelines and two open-source transcription factor binding site identification pipelines use BERT. In addition, three open-source transcription factor binding affinity prediction pipelines use GPT and BERT language models, whereas 8 methyl-adenine and 4 methyl-cytosine modification prediction pipelines use BERT and transformers.

Predictive pipelines can use language models in two different ways: (1) training a language model from scratch (self-training) on a large corpus and (2) leveraging a pre-trained open-source language model and fine-tuning it for specific downstream tasks. Overall, a critical analysis of existing studies reveals that source codes of 20 BERT, 13 Transformer, 4 GPT, and 1 Transformer-XL based predictive pipelines are publicly available. A holistic view of Table 5 reveals that 23 open-source predictive pipelines perform self-training of different language models from scratch for 20 tasks, whereas 15 open-source predictive pipelines have used pre-trained language models for 11 different tasks.

Specifically in 20 BERT-based predictive pipelines, 9 BERT models are self-trained from scratch for nine different tasks, namely, protein-DNA binding site prediction (96), 6mA-methyl adenine modification prediction (144, 281), DNA methylation modification prediction (159, 248), 5mC-methyl cytosine modification prediction (282), nucleosome positioning prediction (29), promoter prediction (93), splice site prediction (93), transcription factor binding site prediction (93), and transcription factor binding affinity prediction (52). In contrast, 11 pre-trained BERT models are utilized to perform 7 downstream tasks, namely, protein-DNA binding site prediction (53), DNA methylation modification (154, 155, 157), 4mC-methyl cytosine modification prediction (143), transcription factor binding affinity prediction (94), DNA replication origin prediction (25), enhancer identification (60, 61, 283), and protein-DNA interface hotspots prediction (284). To facilitate readers, we have summarized uniquely pre-trained language models along with pre-training data for DNA sequence analysis tasks in Table 6.

This section facilitates AI researchers by providing details of performance figures achieved over diverse benchmark datasets for all three kinds of predictive pipelines, namely, word embedding, language models, and nucleotide compositional and positional information across 44 distinct DNA sequence analysis tasks. To assist researchers for developing novel predictive pipelines, we have thoroughly analyzed literature and identified the current state-of-the-art predictor for each task. Section 3 provides categorization of 44 DNA sequence analysis tasks into 8 different categories. In this section, we have summarized the performance values of the predictive pipelines for these 44 tasks into 7 different Tables. Each Table corresponds to the predictive pipelines of tasks within one category, except for 1 Table that includes predictive pipelines related to tasks from 3 different categories. Within these Tables, highlighted predictors represent state-of-the-art performance values on public datasets across each task. Furthermore, this section also facilitates crucial information that which of the tasks of every goal offer more room for improvement through the development of more robust and effective predictive pipelines.

Table 7 summarizes the crucial details of seven DNA sequence analysis tasks classified under the hood of genome structure and stability. Overall, for genome structure and stability goal, four unique representation learning methods, namely, BERT, Transformer, Word2vec, and multi-scale convolution, in conjunction with bi-directional gated recurrent unit methods are used across seven different tasks. Similarly, six unique classifiers, namely, BERT, LSTM, Transformer, CNN+LSTM, CapsNet, and CNN, are used in seven different task predictive pipelines. Most commonly used representation learning scheme for this goal is BERT followed by Transformer. BERT is most commonly used with a self-classifier for three different tasks and used with LSTM classifier for one task. Transformer is used with only self-classifier for three different tasks. Word2vec potential is explored with CNN-based classifiers for two different tasks and multi-scale convolution in conjunction with bi-directional gated recurrent unit method is only explored with CNN classifier for one task. Overall, among all predictive pipelines, BERT with self-classifier or LSTM classifier manages to achieve top performance figures as compared to transformer-based predictive pipelines. Among all 7 tasks, genome structure analysis and long range chromatin interaction prediction tasks provide a lot of room for improvement as the performance of their predictive models fall below 70%. BERT or Transformer with CapsNet classifier-based predictive pipeline can potentially enhance the performance on either or both of these tasks.

Furthermore, Table 8 provides a high-level overview of the performance achieved by 48 predictors for 9 DNA sequence analysis tasks classified under the hood of gene expression regulation. Overall, for gene expression regulation goal, 10 unique representation learning methods, namely, ULMFiT, BERT, One-hot encoding, Word2vec, FastText, C2+NCP, Node2vec+SocDim+Grarep, ELECTRA, ALBERT, and Transformer, are used across 9 different tasks. Overall, 14 unique classifiers are employed in these predictive pipelines, namely, CNN, MLP, DF, CNN+BiLSTM, CNN+LSTM, SVM, Siamese network, DenseNet, CatBoost, TCN, XGBoost, RF+CNN, LSTM, BiGRU, and CNN+BiGRU.

For this goal, most commonly used representation learning approach is BERT. BERT is used with five different classifiers across six unique tasks. BERT with self-classifier is evaluated across all six unique tasks, whereas BERT with other four classifiers is evaluated on some of these six tasks. Specifically, BERT with CNN classifier is evaluated on four common tasks, namely, enhancer identification, promoter identification, protein-DNA binding site prediction, and transcription factor binding site prediction. BERT with DF, RF, and XGBoost is evaluated on one common task each including enhancer identification, protein-DNA binding site prediction, and promoter identification. Among all BERT-based predictive pipelines, BERT achieves the best performance with CNN classifier on two tasks, namely, transcription factor binding site prediction and protein-DNA binding site prediction. Second most common representation learning approach for this goal is Word2vec that is explored with seven different classifiers for four different tasks. Specifically, Word2Vec with CNN and CNN+BiLSTM is used for one task, with LSTM, TCN, and RF+CNN for one task, with BiGRU for one task, and with CNN+BiGRU for one task. Among all Word2vec-based predictive pipelines, Word2Vec achieves the best performance with CNN+BiGRU classifier on enhancer-promoter interaction prediction task. From two most common approaches, BERT with CNN and self-classifiers manages to yield top performance values as compared to Word2vec-based predictive pipelines. Beyond BERT and Word2vec, transformer-XL is used with CNN for two different tasks, ALBERT and ELECTRA are used with self-classifiers for a single task, and ULMFiT is used with CNN for a single task. In addition, potential of transformer is explored with CNN for one task and with a self-classifier for two tasks. FastText-based representation learning is used with MLP and SVM classifiers for a single task and potential of three graph embedding, namely, Node2Vec, SocDim, and GraRep, is explored with CatBoost classifier for a single task. Overall, among all approaches, ULMFiT manages to achieve best performance with CNN classifier on enhancer identification task. From all nine tasks, protein-DNA binding site prediction and protein-DNA binding affinity prediction have some room for improvement. Considering the promising performance trends for this goal, Word2vec potential can be explored with CNN+BiGRU classifier and ULMFiT potential can be explored with standalone CNN as well as ensemble CNN+BiGRU classifier to enhance the performance of under-performing tasks.

In addition, Table 9 summarizes predictive models developed for seven different DNA sequence analysis tasks classified under the hood of gene analysis. For gene analysis goal, 12 unique representation learning methods are used that include Gapped K-mer Encoding, ESM-2, Flux Sampling, Node2Vec, FastText, OPA2Vec, Transformer, Laplacian eigenmaps + Locally linear Embedding + DeepWalk + Node2Vec, and GPT. Overall, eight unique classifiers, namely, GCNN, GNN, GAT, kNN, RF, SVM, CNN, and MLP, are used in different predictive pipelines. Most commonly used representation learning scheme for this goal is Node2vec followed by FastText. Node2vec is used with GCNN classifier for three different tasks and with GAT and MLP classifiers for two different tasks, whereas FastText is used with an ensemble and MLP classifiers for two different tasks. From most commonly used approaches, Node2Vec performs better in the majority of tasks and achieve top performance with GAT classifier as compared to FastText approach. Apart from Node2Vec and FastText, potential of ESM-2 along with a self-classifier and flux sampling with GNN is explored for a single task, transformer with CNN is evaluated for two different tasks, and GPT is used with a self-classifier for two tasks. In addition, OPA2Vec is used with RF for one task, Gapped K-mer encoding with GCN classifier is used for one task, and potential of Laplacian eigenmaps, Locally linear Embedding, DeepWalk, and Node2Vec is explored with RF for one task. In the holistic view, among all approaches, Gapped K-mer Encoding approach with GCNN classifier achieves the best performance for essential gene identification task. Among all seven distinct tasks, multi-label classification task, namely, gene function prediction provides a lot of room for improvement as the performance of its respective predictive pipeline based on Node2vec and GCNN classifier fall below 60%. Considering the promising performance of Gapped K-mer Encoding method, Gapped K-mer Encoding method and GCNN-based predictive pipeline can prove fruitful for various low performance tasks such as gene function prediction.

Moreover, Table 10 summarizes eight DNA sequence analysis tasks classified across three unique biological goals, namely, DNA modification prediction, environmental and microbial genomics, and gene network analysis. For DNA modification prediction goal, across 4 DNA sequence analysis tasks, 27 predictors are developed. In the predictive pipelines, overall 10 unique representation learning methods are used which include PSeKNC, BERT, nucleotide physico-chemical properties and occurrence frequency based encoder, Transformer-XL, Word2Vec, One-hot encoding, FastText, ULMFIT, and BERT+ ALBERT+XLNet+ ELECTRA. Similarly, nine unique classifiers, namely, Structural Sparse Regularized Random Vector Functional Link Network, CatBoost, KNN, CNN, BiLSTM, CNN+BiLSTM, SVM, XGBoost, and FGM, are employed in different predictive pipelines. For DNA modification prediction goal, most commonly used representation learning approach is BERT. BERT is used with five different classifiers for all four tasks. Specifically, BERT with a self-classifier is evaluated for three tasks, namely, 4mC-methyl cytosine, 5mC-methyl cytosine, and DNA methylation modification prediction. BERT is also used with two other classifiers, namely, CatBoost, and FGM, for two common tasks, namely, 4mC-methyl cytosine modification prediction, and DNA methylation modification prediction. In addition, BERT is used with CNN and CNN+BiLSTM classifier for one task, namely, 6mA-methyl adenine modification prediction. Among all BERT-based predictive pipelines, BERT with a self-classifier showed top performance values for two tasks, namely, 5mC-methyl cytosine modification prediction, and DNA methylation modification prediction.

Second most commonly used representation learning approach in this goal is Word2vec which is explored with two unique classifiers for two different tasks. Specifically, Word2vec with CNN classifier is used for one task, namely, 4mC-cytosine modification prediction, and with BiLSTM for one task, namely, 6mA-methyl adenine modification prediction. From most common approaches, BERT manages to achieve best performance with a self-classifier as compared to Word2vec-based predictive pipeline. Apart from BERT and Word2vec, Transformer with a self-classifier is used for three tasks, namely, 5mC-methycyctosine modification prediction, 6mA-methyl adenine modification prediction, and DNA methylation modification prediction. Transformer is also used with CNN classifier on one of the common task, namely, 6mA-methyl adenine modification prediction. Furthermore, potential of transformer-XL is explored with CNN classifier for one task, ULMFiT and hybrid encoding scheme (BERT+ALBERT+XLNet+ELECTRA) with self-classifier for one task, FastText with SVM classifier for one task and FastText with XGBoost classifier for one task. Overall, among all approaches, PseKNC encoding approach with structural sparse regularized random vector functional link network classifier manages to achieve best predictive performance on 4mC-methylcytosine modification prediction. Among all four tasks, DNA methylation modification prediction and 5mC-methyl cytosine modification prediction have some room for improvement. Building on the performance trends of predictive pipelines developed for different tasks of this goal, potential of BERT or PseKNC representation learning approach with structural sparse regularized random vector functional link network classifier can be explored to enhance the performance of under-performing tasks.

For environmental and microbial genomics goal, only potential of BERT representation learning is explored with a self-classifier. However, the potential of neural word embeddings and domain specific encoders based predictive pipelines remains unexplored.

For gene network analysis goal, across two different tasks, four unique representation learning approaches, namely, FastText, Node2vec, BERT, and metabolic encoding, along with four unique classifiers, namely, MLP, LightGBM, Clustering algorithm, and PCT, are used by six predictors. FastText representation learning is most commonly used among all approaches. Specifically, FastText along with MLP classifier is used for gene taxonomy classification task. Second most common representation learning approach is BERT that is used with a self-classifier for same gene taxonomy classification task. Apart from this, Node2Vec representation is explored with PCT classifier and metabolic feature encoding is explored with clustering algorithm for gene network reconstruction task. Among all approaches, FastText and MLP classifier-based predictive pipeline manages to achieve best performance for gene taxonomy classification task. Among all tasks of this goal, gene taxonomy classification offers some room for improvement. Building on promising performance achieved by contemporary language models for different sequence analysis tasks, hierarchical graph transformer and sophisticated machine or deep learning-based ensemble classifier can further raise the predictive performance on gene taxonomy classification task. Furthermore, advanced graph-based representation learning methods, GraRep, HOPE, and LINE with deep classifiers can also potentially raise the predictive performance on gene taxonomy classification task.

In addition, Table 11 provides an overview of six DNA sequence analysis tasks classified under the goal of DNA functional analysis. For this goal, four unique representation learning methods, namely, Word2Vec, Transformer, BERT, and FastText, are used in conjunction with three different predictors, namely, LogR, SVM, and cosine similarity. Among all four representation learning methods, Transformer is most commonly used followed by Word2vec and BERT. Transformer is used in three different tasks with self-classifier, Word2vec, and BERT are used with LogR and self-classifier in two different tasks. In addition, potential of FastText is explored with SVM for 1 task. Among all representation learning methods, Transformer with self-classifier manages to achieve top performance for tumor type prediction. Among all six tasks, disease risk estimation task offers a room for improvement as its respective BERT and self-classifier-based predictive pipeline accuracy falls approximately 56%. Hybrid approaches combining the powers of Transformer, BERT, and Word2vec with sophisticated machine learning classifier such as deep forest or deep learning classifiers such as CNN and CNN+BiGRU can potentially enhance the performance on under-performing tasks. Furthermore, except for two tasks, namely, species classification and functional prioritization, of non-coding variants, all other four tasks are evaluated on a single benchmark dataset. Considering deep learning models require huge amount of data to achieve promising performance, development, and utilization of more datasets in model building and validation can also prove fruitful for enhancing the predictive performance.

Finally, Table 12 summarizes predictive models developed for seven unique DNA sequence analysis tasks categorized under the goal of disease analysis. For this goal, seven unique representation learning methods, namely, Node2Vec, Graph2Vec, BERT, Graph Embedding, SDNE, Word2Vec, and Transformer, and five predictors, namely, MLP, RF, cosine similarity, clustering, and BERT self-classifier, are used in different tasks. Among all representation learning approaches, BERT and Word2vec are most commonly used. BERT is used with self-classifier on two different tasks, and word2vec is used with cosine similarity for a multi-class classification task, namely, mutation susceptibility analysis and with clustering algorithm for an only clustering task, namely, phylogenetic analysis. Apart from BERT and Word2vec, other representation learning methods Node2vec+Graph2vec, Graph Embedding, SDNE+Word2vec, and Transformer are used on one classification task each with MLP and self-classifiers. Overall, among all approaches, Transformer with self-classifier-based predictive pipelines manages to achieve best performance on tumor type prediction task. Among all seven tasks, disease risk estimation task offers a lot of room for improvement as its respective BERT with self-classifier-based predictive pipeline performance falls approximately 56%. Taking the transformer performance trends into account, latest sophisticated language models such as hierarchical graph transformer, ELECTRA, and GPT-4 along with ensemble machine or deep learning predictors can achieve significance performance rise in under-performing classification and clustering tasks.

In a nutshell, a comprehensive analysis of state-of-the-art predictive pipelines developed using word embeddings, language models, and nucleotide compositional and positional information-based encoders reveals interesting trends. From 44 DNA sequence analysis tasks classified under the hood of 8 major biological goals, 24 tasks belong to binary classification, 4 belong to interaction prediction, 11 belong to multi-class classification, only 3 belong to multi-label classification, 1 belong to regression, and 1 belong to clustering. Overall, 25 unique representation learning methods and 28 predictors are explored for developing robust predictive pipelines for 44 DNA sequence analysis tasks classified under the hood of 8 major biological goals. Across all eight goals, language model-based representation learning approaches and deep learning classifiers are achieving better performance across majority of the tasks. Researchers can explore the performance potential of latest transformer-based language models such as Hierarchical graph transformer, GPT-4, and hybrid representation learning methods along with sophisticated ensemble machine learning or deep learning predictors for different classification, regression, and clustering tasks.

This section provides an overview of 44 distinct DNA sequence analysis task-related articles distribution across conferences, journals, and publishers. Before paper submission, identification of relevant journals for a study publication in the interdisciplinary field of AI applications in DNA sequence analysis is an important task. There are three types of journals in AI and DNA sequence analysis fields: (1) Journals focusing on core AI algorithms, (2) Journals dedicated to core biological findings, (3) Hybrid journals that publish research integrating both AI algorithms and biological data. Researchers often face desk rejections when submitting to core AI or biology journals. Instead, they should target hybrid journals. While many tools exist to find suitable journals, this comprehensive guide provides detailed information to help researchers to identify journals where applications using word embeddings and large language models for DNA sequence analysis are published.

Figure 7 graphically depicts distribution of 127 studies across 53 journals, 1 transactions, 3 conferences, and 2 pre-print repositories. Among all journals, more studies are published in Briefings in Bioinformatics followed by Bioinformatics, Computational Biology, and Chemistry, and International Journal of Molecular Sciences. Similarly, among all conferences, more studies are published in the International Conference on Bioinformatics and Biomedicine (BIBM) followed by the 11^th Hellenic Conference on Artificial Intelligence, Proceedings of the 12th and 13^th ACM International Conference on Bioinformatics, Computational Biology, and Health Informatics. Moreover, 5 studies are published in ACM transaction of computational biology. In the light of rapid development in research findings, researchers have also published 24 studies in bioRxiv, ArXiV, and MedXiv platforms. However, researchers generally prefer journal publications for their sustained impact.

Furthermore, Figure 8 illustrate that 127 DNA sequence analysis studies are published by 17 different publishers, namely, Springer,⁹ Elsevier (see text footnote ³), Oxford University Press,¹⁰ Cold Spring Harbor Laboratory,¹¹ IEEE,¹² Ozer UYGUN,¹³ ACS Publication,¹⁴ Frontier Media SA,¹⁵ Gazi University,¹⁶ Marry Ann Liebert,¹⁷ MDPI,¹⁸ National Acad Sciences,¹⁹ Nature Publishing Group UK London,²⁰ PeerJ Inc.,²¹ Public Library of science,²² ACM (see text footnote ²), and pre-prints.²³ Notably, approximately 60 out of 127 DNA sequence analysis studies are published by Oxford University Press, Elsevier, and Cold Spring Harbor Laboratory. In addition, IEEE, Springer, and MDPI have contributed 30 relevant papers. Furthermore, 32 DNA sequence analysis research articles are published by ACS Publications, Frontiers Media SA, Mary Ann Liebert, Inc., National Acad Sciences, Nature Publishing Group UK London, Public Library of Science, PeerJ Inc, and others. Collectively, 96 are journal publications, 6 are conference papers, 1 is transaction articles, and 24 are pre-prints out of 127 DNA sequence analysis studies published by 21 different publishers. This comprehensive analysis across various journals, conferences, transactions, and pre-print repositories highlights diverse and extensive research landscape in DNA sequence analysis.

We acknowledge that “DNA sequence analysis” encompasses a much broader range of bioinformatics applications than covered in this review. Our focus is specifically on AI-based approaches that analyze raw DNA sequence data to predict biological functions and features. Other important areas of bioinformatics such as genome assembly, comprehensive variant analysis, phylogenomics, and many aspects of population genetics utilize different computational approaches and would benefit from separate dedicated reviews. A comprehensive review of existing literature on AI-driven DNA sequence analysis tasks reveals a significant inconsistency in the evaluation of predictive pipelines across similar datasets. Researchers have developed numerous datasets tailored to specific tasks, and most of the researchers have evaluated their proposed predictors solely on their own datasets.

The creation of new datasets is essential because public databases are frequently updated with new sequence information. These new datasets can incorporate the most recent sequence data alongside existing information. Moreover, existing datasets tend to be smaller, while deep learning models perform better with larger datasets. To address performance comparison inconsistency, there is an urgent need to standardize dataset utilization. One potential solution is to benchmark existing predictors on newly developed datasets and compare the performance of proposed predictors against these benchmarks. This approach would provide a more objective evaluation of proposed predictor performance. However, in this context, a significant challenge is the limited availability of source codes for existing predictors. Many studies make their source code private, hindering the reproducibility of results and direct comparison with other methods. To streamline the integration of innovative methods and ensure methodological advancement, it is crucial to analyze task-specific datasets and create standardized datasets with detailed descriptions. By benchmarking the performance of existing predictors on these standardized datasets, researchers can establish a common ground for comparison and facilitate more accurate evaluations of models. This approach would enhance transparency and reproducibility in DNA sequence analysis studies.

The development of AI-driven predictive pipelines for DNA sequence analysis relies heavily on effective sequence representation learning methods and appropriate machine or deep learning models. Machine and deep learning models inherently depend on statistical vectors and cannot process raw DNA sequences directly. Therefore, the role of representation learning methods in these pipelines is crucial. These methods are responsible for transforming raw DNA sequences into statistical vectors by capturing and encoding the most informative nucleotide patterns.

In the current landscape of AI-driven DNA sequence analysis, researchers have employed a variety of representation learning methods, including 12 distinct word embedding techniques and 8 language models. However, when it comes to other genetic molecules such as RNA and proteins, researchers have explored an additional set of 17 word embedding methods and 13 language models that have not yet been applied to DNA sequence analysis. These unexplored word embedding methods include DANE (285), ELMo (286–288), GATNE (289), GEMSEC (290), MetaGraph2Vec (291), HAKE (292), HIN2Vec (293), HOPE (294, 295), LINE (296–298), Mashup (299, 300), Random Watcher-Walker (RW2) (301), RotatE (292, 302, 303), RWR (304), Struc2Vec (305, 306), SVD (307, 308), Topo2Vec (309), and TransE (310), while the unexplored language models include AlphaFold (311–315), AlphaFold2 (316, 317), BigBird (318), ESM-1 (315, 319, 320), ESM-2 (109, 286, 316, 320), Graph Transformer Network (321), Heterogeneous Graph Transformer (322), IgFold (323), LongFormer (318), RoBERTa (324, 325), T5 (320, 326–328), and Vision Transformer (288). Integrating these advanced word embedding techniques and large language models into AI-driven DNA sequence analysis pipelines could potentially enhance their performance and robustness.

Within 127 AI-driven DNA sequence analysis predictive pipelines, researchers have utilized 18 machine and deep learning algorithms at the predictor level. In some cases, they have developed meta-predictors by combining multiple machine learning and deep learning algorithms to enhance predictive performance. However, similar to the representation learning stage, there are 24 distinct methods at the predictor level that have not yet been explored, representing untapped potential for improving the accuracy and robustness of these AI-driven pipelines.

Our categorization of 44 distinct tasks into 8 biological goals provides a structured framework that serves as a valuable starting taxonomy for both computer scientists and life scientists. This organization is informed by both computational and biological literature and creates a common reference point that bridges these disciplines while facilitating interdisciplinary communication. We recognize the inherent complexity of biological systems and the interconnected nature of many of these tasks. For example, enhancer identification categorized under gene expression regulation shares biological connections with chromatin accessibility prediction categorized under genome structure and stability. Nevertheless, this framework offers a practical organizing principle that will naturally evolve and be refined over time. The taxonomy presented here lays groundwork that future collaborative efforts between AI researchers and domain specialists in genomics can build upon. We anticipate gradual development into a more nuanced framework that maintains practical utility while better reflecting biological realities. Similar to many scientific classification systems, we expect this taxonomy to mature through iterative refinement as the field advances.

This review serves as a comprehensive resource for researchers working at the intersection of AI and DNA sequence analysis. It provides a structured foundation for future innovations in the rapidly evolving field of computational genomics. It bridges the critical gap between molecular biology and artificial intelligence by systematically analyzing 44 different DNA sequence analysis tasks, their associated databases, datasets, and AI methodologies. It identifies 36 biological databases and 140 benchmark datasets that provide a robust foundation for developing and evaluating AI predictors. Furthermore, our examination of existing predictive pipelines demonstrates the successful application of 39 word embeddings and 67 language models across various DNA sequence analysis tasks. Our analysis reveals that while significant progress has been made in developing AI-driven predictive pipelines for DNA sequence analysis, several challenges and opportunities remain unexplored. Several promising directions emerge for the advancement of this field. First, the integration of 17 unexplored word embedding methods and 13 language models (currently utilized only for RNA and protein analysis) could significantly enhance DNA sequence analysis capabilities. Second, the development of standardized benchmark datasets and evaluation protocols would facilitate fair comparisons between different predictive models and accelerate progress in the field. Third, the adoption of 24 untapped machine learning and deep learning algorithms at the predictor level presents an opportunity to improve prediction accuracy and robustness.

Future research should focus on developing multi-task learning frameworks that can simultaneously handle multiple DNA sequence analysis tasks, thereby improving computational efficiency and leveraging shared biological features. Furthermore, ensuring public accessibility of source codes and detailed documentation of predictive pipelines would foster reproducibility and collaborative advancement in the field. The establishment of standardized performance metrics and evaluation protocols across different DNA sequence analysis tasks would enable more meaningful comparisons between various approaches and guide future developments. As DNA sequence data continue to grow exponentially, the integration of more sophisticated AI architectures, particularly those capable of handling large-scale genomic data efficiently, will become increasingly important. Our categorization of 44 tasks reflects common AI applications in DNA sequence analysis literature and provides a starting point for interdisciplinary discourse. We recognize that deeper collaboration between AI researchers and life scientists would further strengthen the biological relevance of this framework. A greater amount of input from geneticists and bioinformaticians would be essential to develop a more comprehensive and biologically relevant tasks taxonomy.