RT Journal Article
SR Electronic
T1 Why are frameshift homologs widespread within and across species?
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 067736
DO 10.1101/067736
A1 Xiaolong Wang
A1 Quanjiang Dong
A1 Gang Chen
A1 Jianye Zhang
A1 Yongqiang Liu
A1 Jinqiao Zhao
A1 Haibo Peng
A1 Yalei Wang
A1 Yujia Cai
A1 Xuxiang Wang
A1 Chao Yang
YR 2016
UL http://biorxiv.org/content/early/2016/08/25/067736.abstract
AB Frameshifted coding genes presumably yield truncated and dysfunctional proteins. We report that frameshift homologs, including frameshift orthologs and frameshift paralogs, are actually widespread within and across species. We proposed that protein coding genes have a ca-0.5 quasi-constant shiftability: given any protein coding sequence, at least 50% of the amino acids remain conserved in a frameshifted protein sequence. In the natural genetic code, amino acid pairs assigned to frameshift codon substitutions are more conserved than those to random codon substitutions, and the frameshift tolerating ability of the natural genetic code ranks among the best 6% of all compatible genetic codes. Hence, the shiftability of protein coding genes was mainly predefined by the standard genetic code, while additional sequence-level shiftability was achieved through biased usages of codons and codon pairs. We concluded that during early evolution the genetic code was symmetrically optimized for tolerate frameshifts, so that protein coding genes were endowed an inherent ability to tolerate frameshifting in both forward and backward directions.