Rapid Evolution of Gained Essential Developmental Functions of a Young Gene via Interactions with Other Essential Genes
Rapid Evolution of Gained Essential Developmental Functions of a Young Gene via Interactions with Other Essential Genes
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DOI：
10.1093/molbev/msz137
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发表时间：
2019-10-01
影响因子：
10.7
通讯作者：
Long, Manyuan
中科院分区：
文献类型：
--
作者：
Lee, Yuh Chwen G.;Ventura, Iuri M.;Long, Manyuan
新基因是最近才出现的，只存在于一个系统发育中的一个物种子集中。越来越多的证据表明，新基因，就像跨物种保守的旧基因一样，也可以承担重要的功能，对生物体的生存和繁殖成功至关重要。尽管对新基因获得生育功能的机制有详细的分析，但新基因如何迅速成为生存能力所必需的仍不清楚。我们重点研究了果蝇中一个年轻的逆转录复制基因（CG7804，我们将其命名为Cocoon），它起源于4 - 10 Ma之间。我们发现，与保守的亲本基因不同，蚕茧是在正向选择下进化的，在亲本基因的功能位点上积累了许多氨基酸差异。尽管它很年轻，但茧对于黑腹果蝇的多个发育阶段（包括关键的胚胎阶段）的生存是必不可少的，并且它的表达在与其亲本基因不同的组织中是必不可少的。功能基因组分析发现，蚕茧获得了独特的dna结合位点，并对基因表达产生了与其亲本基因截然不同的影响。重要的是，茧结合主要定位于具有其他基本功能和/或具有多个基因相互作用的基因，这表明茧通过形成对基因相互作用网络有重大影响的相互作用获得了新的生存基本功能。我们的研究是破译新基因在功能上与亲本基因分化并成为必需的进化轨迹的重要一步。
New genes are of recent origin and only present in a subset of species in a phylogeny. Accumulated evidence suggests that new genes, like old genes that are conserved across species, can also take on important functions and be essential for the survival and reproductive success of organisms. Although there are detailed analyses of the mechanisms underlying new genes' gaining fertility functions, how new genes rapidly become essential for viability remains unclear. We focused on a young retro-duplicated gene (CG7804, which we named Cocoon) in Drosophila that originated between 4 and 10 Ma. We found that, unlike its evolutionarily conserved parental gene, Cocoon has evolved under positive selection and accumulated many amino acid differences at functional sites from the parental gene. Despite its young age, Cocoon is essential for the survival of Drosophila melanogaster at multiple developmental stages, including the critical embryonic stage, and its expression is essential in different tissues from those of its parental gene. Functional genomic analyses found that Cocoon acquired unique DNA-binding sites and has a contrasting effect on gene expression to that of its parental gene. Importantly, Cocoon binding predominantly locates at genes that have other essential functions and/or have multiple gene-gene interactions, suggesting that Cocoon acquired novel essential function to survival through forming interactions that have large impacts on the gene interaction network. Our study is an important step toward deciphering the evolutionary trajectory by which new genes functionally diverge from parental genes and become essential.