The diversity of body plans of mammals accelerates the innovation of lifestyles and the extensive adaptation to different habitats,including terrestrial,aerial and aquatic habitats.However,the genetic basis of those p...The diversity of body plans of mammals accelerates the innovation of lifestyles and the extensive adaptation to different habitats,including terrestrial,aerial and aquatic habitats.However,the genetic basis of those phenotypic modifications,which have occurred during mammalian evolution,remains poorly explored.In the present study,we synthetically surveyed the evolutionary pattern of Hox clusters that played a powerful role in the morphogenesis along the head-tail axis of animal embryos and the main regulatory factors(Mll,Bmi1 and E2f6)that control the expression of Hox genes.A deflected density of repetitive elements and lineage-specific radical mutations of Mll have been determined in marine mammals with morphological changes,suggesting that evolutionary changes may alter Hox gene expression in these lineages,leading to the morphological modification of these lineages.Although no positive selection was detected at certain ancestor nodes of lineages,the increasedωvalues of Hox genes implied the relaxation of functional constraints of these genes during the mammalian evolutionary process.More importantly,49 positively-selected sites were identified in mammalian lineages with phenotypic modifications,indicating adaptive evolution acting on Hox genes and regulatory factors.In addition,3 parallel amino acid substitutions in some Hox genes were examined in marine mammals,which might be responsible for their streamlined body.展开更多
基金This work was supported by the National Natural Science Funds for Distinguished Young Scholars to G.Y.(grant number 31325025)the State Key Program of National Natural Science Foundation of China(NSFC)(grant number 31630071)+2 种基金the NSFC(grant numbers 31570379 to S.X.,31370401 to W.R.)the Priority Academic Program Development of Jiangsu Higher Education Institutions to G.Y.and S.X.the Natural Science Foundation of Jiangsu Province of China(grant number BK20141449)to S.X.
文摘The diversity of body plans of mammals accelerates the innovation of lifestyles and the extensive adaptation to different habitats,including terrestrial,aerial and aquatic habitats.However,the genetic basis of those phenotypic modifications,which have occurred during mammalian evolution,remains poorly explored.In the present study,we synthetically surveyed the evolutionary pattern of Hox clusters that played a powerful role in the morphogenesis along the head-tail axis of animal embryos and the main regulatory factors(Mll,Bmi1 and E2f6)that control the expression of Hox genes.A deflected density of repetitive elements and lineage-specific radical mutations of Mll have been determined in marine mammals with morphological changes,suggesting that evolutionary changes may alter Hox gene expression in these lineages,leading to the morphological modification of these lineages.Although no positive selection was detected at certain ancestor nodes of lineages,the increasedωvalues of Hox genes implied the relaxation of functional constraints of these genes during the mammalian evolutionary process.More importantly,49 positively-selected sites were identified in mammalian lineages with phenotypic modifications,indicating adaptive evolution acting on Hox genes and regulatory factors.In addition,3 parallel amino acid substitutions in some Hox genes were examined in marine mammals,which might be responsible for their streamlined body.
