Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: Research Article Variation in the Correlation of G + C Composition with Synonymous Codon Usage Bias among Bacteria | Hindawi Publishing Corporation EURASIP Journal on Bioinformatics and Systems Biology Volume 2007 Article ID61374 7 pages doi 2007 61374 Research Article Variation in the Correlation of G C Composition with Synonymous Codon Usage Bias among Bacteria Haruo Suzuki Rintaro Saito and Masaru Tomita Institute for Advanced Biosciences Keio University Yamagata 997-0017 Japan Received 31 January 2007 Accepted 4 June 2007 Recommended by Teemu Roos G C composition at the third codon position GC3 is widely reported to be correlated with synonymous codon usage bias. However no quantitative attempt has been made to compare the extent of this correlation among different genomes. Here we applied Shannon entropy from information theory to measure the degree of GC3 bias and that of synonymous codon usage bias of each gene. The strength of the correlation of GC3 with synonymous codon usage bias quantified by a correlation coefficient varied widely among bacterial genomes ranging from to . Previous analyses suggesting that the relationship between GC3 and synonymous codon usage bias is independent of species are thus inconsistent with the more detailed analyses obtained here for individual species. Copyright 2007 Haruo Suzuki et al. This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited. 1. INTRODUCTION Most amino acids can be encoded by more than one codon . a triplet of nucleotides such codons are described as being synonymous and usually differ by one nucleotide in the third position. In many organisms alternative synonymous codons are not used with equal frequency. Various factors have been proposed to contribute to synonymous codon usage bias including G C composition replication strand bias and translational selection 1 . Here we focus on the contribution of G C composition to synonymous codon usage bias. G
