Analysis of synonymous codon usage patterns in sixty-four different bivalve species

Area of Science:

• Marine Biology
• Genomics
• Evolutionary Biology

Background:

• Synonymous codon usage bias (CUB) is the non-random use of codons that code for the same amino acid.
• CUB is observed in all organisms, but the factors shaping it are not fully understood.
• Limited genomic data has hindered CUB analysis in bivalve mollusks.

Purpose of the Study:

• To investigate codon usage preferences in 64 bivalve species.
• To identify factors contributing to CUB in bivalves.
• To provide a comprehensive overview of CUB in this important marine invertebrate class.

Main Methods:

• Utilized massive sequence data from next-generation sequencing projects.
• Analyzed codon preferences across six major evolutionary lineages of Bivalvia.
• Compared CUB patterns and their correlation with phylogeny and other factors.

Main Results:

• Detected significant interspecies differences in CUB, only partially explained by phylogeny.
• Observed mild CUB in most species, with notable exceptions showing higher bias and AT-ending codon preference (e.g., Arcida, Mytilida).
• Demonstrated that mutational bias, translational efficiency, and accuracy selection contribute to bivalve CUB.

Conclusions:

• CUB in bivalves is heterogeneous and influenced by multiple evolutionary forces.
• This study offers the first broad overview of CUB in the class Bivalvia.
• Further research is needed to fully elucidate the mechanisms underlying bivalve CUB.