Linkage-based ortholog refinement in bacterial pangenomes with CLARC

Area of Science:

• Genomics
• Bioinformatics
• Evolutionary Biology

Background:

• Bacterial genomes show substantial variation in gene content and sequence.
• Pangenome analysis classifies genes into core and accessory clusters of orthologous groups (COGs).
• Current methods may misclassify divergent alleles, inflating accessory gene counts.

Purpose of the Study:

• To introduce CLARC (Connected Linkage and Alignment Redefinition of COGs), a novel tool for refining pangenome analyses.
• To improve the accuracy of classifying orthologous groups by condensing accessory COGs.
• To enhance evolutionary predictions derived from comparative genomics.

Main Methods:

• CLARC utilizes functional annotation and linkage information to condense accessory COGs.
• The tool redefines orthologous groups into more practical units for evolutionary analysis.
• CLARC was applied to analyze over 8000 Streptococcus pneumoniae genomes.

Main Results:

• CLARC significantly reduced accessory gene estimates by over 30% in Streptococcus pneumoniae.
• The refined COG definitions improved the accuracy of evolutionary predictions.
• The tool demonstrated broad applicability across different bacterial species.

Conclusions:

• CLARC provides a more accurate and practical approach to bacterial pangenome analysis.
• The tool refines COG definitions, offering critical insights into bacterial evolution.
• CLARC is a broadly applicable tool for comparative genomics and genetic studies.