Codon Usage Pattern of Genes Involved in Central Nervous System

Abstract

Codon usage bias (CUB) is the non-uniform usage of synonymous codons in which some codons are more preferred to others in the transcript. Analysis of codon usage bias has applications in understanding the basics of molecular biology, genetics, gene expression, and molecular evolution. To understand the patterns of codon usage in genes involved in the central nervous system (CNS), we used bioinformatic approaches to analyze the protein-coding sequences of genes involved in the CNS. The improved effective number of codons (ENC) suggested that the overall codon usage bias was low. The relative synonymous codon usage (RSCU) revealed that the most frequently occurring codons had a G or C at the third codon position. The codons namely TCC, AGC, CTG, CAG, CGC, ATC, ACC, GTG, GCC, GGC, and CGG (average RSCU > 1.6) were over-represented. Both mutation pressure and natural selection might affect the codon usage pattern as evident from correspondence and parity plot analyses. The overall GC content (59.93) was higher than AT content, i.e., genes were GC-rich. The correlation of GC12 with GC3 suggested that mutation pressure might affect the codon usage pattern.

Keywords: Central nervous system; Codon usage bias; Mutation pressure; RSCU.