Codon Usage Bias in Two Hemipteran Insect Species: Bemisia tabaci and Homalodisca coagulata

Codon bias is the nonuniform use of synonymous codons which encode the same amino acid. Some codons are more frequently used than others in several organisms, particularly in the highly expressed genes. The spectacular diversity of insects makes them a suitable candidate for analyzing the codon usage bias. Recent expansion in genome sequencing of different insect species provides an opportunity for studying the codon usage bias. Several works on patterns of codon usage bias were done on Drosophila and other related species but only few works were found in Hemiptera order. We analyzed codon usage in two Hemipteran insect species namely Bemisia tabaci and Homalodisca coagulata. Most frequent codons end with A or C at the 3rd codon position. The ENC (a measure of codon bias) value ranges from 43 to 60 (52.80) in B. tabaci but from 49 to 60 (56.69) in H. coagulata. In both insect species, a significant positive correlation was observed between A and A3%, C and C3%, and GC and GC3%, respectively. Our findings suggest that codon usage bias in two Hemipteran insect species is not remarkable and that mutation pressure causes the codon usage pattern in two Hemipteran insect species.