Divergence in codon usage of Lactobacillus species

Area of Science:

• Microbial Genomics
• Molecular Evolution
• Bacterial Genetics

Background:

• Codon usage bias is a significant phenomenon in microbial genomes.
• Lactobacillus species are important probiotics and food-production microorganisms.
• Understanding codon usage patterns can reveal insights into evolutionary pressures and gene expression.

Purpose of the Study:

• To analyze codon usage patterns across different Lactobacillus species.
• To investigate the factors contributing to codon usage heterogeneity.
• To explore the relationship between codon usage bias, mutational drift, and gene expression.

Main Methods:

• Analysis of codon usage patterns from 70 sequenced genes across various Lactobacillus species.
• Comparison of codon usage bias between and within species.
• Correlation analysis between codon usage bias, mutational drift (GC/AT drift), and gene expression levels.

Main Results:

• High codon usage bias was observed in Lactobacillus, with significant inter- and intra-species heterogeneity.
• Codon usage patterns differed notably between species, partly explained by mutational drift (GC vs. AT drift).
• Highly expressed genes showed greater codon usage bias, and a reduced GC content was found at the 5'-end of genes.

Conclusions:

• Codon usage bias in Lactobacillus is influenced by mutational forces and gene expression levels.
• Species-specific tRNA complements may contribute to observed codon usage differences.
• The findings provide insights into the evolutionary dynamics and translational efficiency of Lactobacillus genes.