The article provides an overview of the KEGG (Kyoto Encyclopedia of Genes and Genomes) database, which is an integrated resource for biological interpretation of genomic data. KEGG aims to assign functional meanings to genes and genomes at both molecular and higher levels. The primary objective is to store molecular-level functions in the KO (KEGG Orthology) database, where each KO represents a functional ortholog of genes and proteins. Higher-level functions are represented through networks of molecular interactions, reactions, and relations in the form of KEGG pathway maps, BRITE hierarchies, and KEGG modules. Key improvements and expansions in KEGG include: 1. **Enhanced KO Database**: The KO database now includes experimentally characterized protein sequences and links to these sequences, improving the coverage of molecular-level functions. 2. **GENES Database**: The GENES database has been expanded to include manually curated sequence data and experimental characterizations, filling gaps in the KO database. 3. **DISEASE and DRUG Databases**: These databases have been improved by systematically analyzing drug labels, integrating disease and drug information with KEGG molecular networks. 4. **KEGG Mapper Tools**: New tools like BlastKOALA and GhostKOALA facilitate automatic annotation and mapping of query sequences to KEGG pathways and modules. 5. **Pathway Maps**: The PATHWAY database continues to be a central resource, with regular updates and new maps added monthly, including disease and drug resistance pathways. 6. **Systematic Analysis of Drug Labels**: KEGG uses systematic analysis of drug labels to improve the DISEASE and DRUG databases, enhancing the integration of research findings with practical applications. KEGG is evolving to become a comprehensive knowledge base for both functional interpretation and practical application of genomic information, making it a valuable resource for researchers and practitioners in genomics and related fields.The article provides an overview of the KEGG (Kyoto Encyclopedia of Genes and Genomes) database, which is an integrated resource for biological interpretation of genomic data. KEGG aims to assign functional meanings to genes and genomes at both molecular and higher levels. The primary objective is to store molecular-level functions in the KO (KEGG Orthology) database, where each KO represents a functional ortholog of genes and proteins. Higher-level functions are represented through networks of molecular interactions, reactions, and relations in the form of KEGG pathway maps, BRITE hierarchies, and KEGG modules. Key improvements and expansions in KEGG include: 1. **Enhanced KO Database**: The KO database now includes experimentally characterized protein sequences and links to these sequences, improving the coverage of molecular-level functions. 2. **GENES Database**: The GENES database has been expanded to include manually curated sequence data and experimental characterizations, filling gaps in the KO database. 3. **DISEASE and DRUG Databases**: These databases have been improved by systematically analyzing drug labels, integrating disease and drug information with KEGG molecular networks. 4. **KEGG Mapper Tools**: New tools like BlastKOALA and GhostKOALA facilitate automatic annotation and mapping of query sequences to KEGG pathways and modules. 5. **Pathway Maps**: The PATHWAY database continues to be a central resource, with regular updates and new maps added monthly, including disease and drug resistance pathways. 6. **Systematic Analysis of Drug Labels**: KEGG uses systematic analysis of drug labels to improve the DISEASE and DRUG databases, enhancing the integration of research findings with practical applications. KEGG is evolving to become a comprehensive knowledge base for both functional interpretation and practical application of genomic information, making it a valuable resource for researchers and practitioners in genomics and related fields.