Evolutionary determinants of genome-wide nucleotide composition.
Hongan LongWay SungSibel KucukyildirimEmily WilliamsSamuel F MillerWanfeng GuoCaitlyn PattersonColin GregoryChloe StraussCasey StoneCécile BerneDavid KyselaWilliam R ShoemakerMario E MuscarellaHaiwei LuoJay T LennonYves V BrunMichael LynchPublished in: Nature ecology & evolution (2018)
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.