Nonsynonymous substitution in abalone sperm fertilization genes exceeds substitution in introns and mitochondrial DNA
Nonsynonymous substitution in abalone sperm fertilization genes exceeds substitution in introns and mitochondrial DNA
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DOI：
10.1073/pnas.95.18.10676
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发表时间：
1998-09-01
影响因子：
11.1
通讯作者：
Vacquier, VD
中科院分区：
文献类型：
--
作者：
Metz, EC;Robles-Sikisaka, R;Vacquier, VD
强阳性达尔文选择作用于两个精子受精蛋白，溶素和18-kDa蛋白，从鲍鱼（Haliotis）。为了了解这种戏剧性的分子进化的系统发育背景下，我们获得了线粒体细胞色素c氧化酶亚基I（mtCOI）的序列，和溶素，18 kDa，和G蛋白亚基的基因组序列。根据mtDNA的分化，四个北太平洋鲍鱼物种在过去的200万年（Myr）内发生了分化，其余的北太平洋物种在400万至2000万年的时间内发生了分化。种间非同义的差异，溶素和18 kDa的外显子超过内含子的核苷酸差异的3.5至24倍。值得注意的是，在一些比较中，溶素和18-kDa基因的非同义取代超过mtCOI的同义取代。从1,200公里范围内收集的多个红鲍个体中测定了赖氨酸和18 kDa内含子/外显子片段的序列。在总共超过29，000个核苷酸的调查中，仅检测到两个核苷酸变化和两个滑移变异位点。然而，mtCOI和G蛋白内含子的多态性被发现在这个物种。这一发现表明，正选择扫一个溶素等位基因和一个18 kDa的等位基因固定。mtCOI和溶素基因树之间的相似性表明，溶素的快速适应性进化一直发生在该组的历史。与mtCOI分子钟校准的比较表明，非同义取代积累2-50倍的速度比在快速进化的哺乳动物基因的溶素和18 kDa的基因。
Strong positive Darvinian selection acts on two sperm fertilization proteins, lysin and 18-kDa protein, from abalone (Haliotis). To understand the phylogenetic context for this dramatic molecular evolution, we obtained sequences of mitochondrial cytochrome c oxidase subunit I (mtCOI), and genomic sequences of lysin, 18-kDa, and a G protein subunit. Based on mtDNA differentiation, four north Pacific abalone species diverged within the past 2 million years (Myr), and remaining north Pacific species diverged over a period of 4-20 Myr. Between-species nonsynonymous differences in lysin and 18-kDa exons exceed nucleotide differences in introns by 3.5- to 24-fold. Remarkably, in some comparisons nonsynonymous substitutions in lysin and 18-kDa genes exceed synonymous substitutions in mtCOI. Lysin and 18-kDa intron/exon segments were sequenced from multiple red abalone individuals collected over a 1,200-km range. Only two nucleotide changes and two sites of slippage variation were detected in a total of >29,000 nucleotides surveyed. However, polymorphism in mtCOI and a G protein intron was found in this species. This finding suggests that positive selection swept one lysin allele and one 18-kDa allele to fixation. Similarities between mtCOI and lysin gene trees indicate that rapid adaptive evolution of lysin has occurred consistently through the history of the group. Comparisons with mtCOI molecular clock calibrations suggest that nonsynonymous substitutions accumulate 2-50 times faster in lysin and 18-kDa genes than in rapidly evolving mammalian genes.