Evolutionary determinants of genome-wide nucleotide composition
Hongan Long, Way Sung, Sibel Kucukyildirim, Emily Williams, Samuel F. Miller, Wanfeng Guo, Caitlyn Patterson, Colin Gregory, Chloe Strauss, Casey Stone, Cécile Berne, David Kysela, William R. Shoemaker, Mario E. Muscarella, Haiwei Luo, Jay T. Lennon, Yves V. Brun & Michael Lynch
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Evolutionary genetics Molecular evolution
Received: 21 May 2017 Accepted: 21 November 2017
Published online: 01 January 2018
Source/Fonte: Shutterstock
Abstract
One of the long-standing mysteries of evolutionary genomics is the source of the wide phylogenetic diversity in genome nucleotide composition (G + C versus A + T), which must be a consequence of interspecific differences in mutation bias, the efficiency of selection for different nucleotides or a combination of the two. We demonstrate that although genomic G + C composition is strongly driven by mutation bias, it is also substantially modified by direct selection and/or as a by-product of biased gene conversion. Moreover, G + C composition at fourfold redundant sites is consistently elevated above the neutral expectation—more so than for any other class of sites.
