Zigler Kirk S, McCartney Michael A, Levitan Don R, Lessios H A
Smithsonian Tropical Research Institute, Balboa, Panama.
Evolution. 2005 Nov;59(11):2399-404.
Studies on the evolution of reproductive proteins have shown that they tend to evolve more rapidly than other proteins, frequently under positive selection. Progress on understanding the implications of these patterns is possible for marine invertebrates, where molecular evolution can be linked to gamete compatibility. In this study, we surveyed data from the literature from five genera of sea urchins for which there was information on gamete compatibility, divergence of the sperm-egg recognition protein bindin, and mitochondrial divergence. We draw three conclusions: (1) bindin divergence at nonsynonymous sites predicts gamete compatibility, whereas (2) bindin divergence at synonymous sites and mitochondrial DNA divergence do not, and (3) as few as 10 amino acid changes in bindin can lead to complete gamete incompatibility between species. Using mitochondrial divergence as a proxy for time, we find that complete gamete incompatibility can evolve in approximately one and a half million years, whereas sister species can maintain complete gamete compatibility for as long as five million years.
对生殖蛋白进化的研究表明，它们往往比其他蛋白进化得更快，且常常处于正选择之下。对于海洋无脊椎动物来说，理解这些模式的影响是有可能的，因为在这类动物中分子进化与配子兼容性相关联。在本研究中，我们查阅了文献中来自五个海胆属的数据，这些数据包含配子兼容性、精卵识别蛋白结合素的分歧以及线粒体分歧的信息。我们得出三个结论：（1）非同义位点的结合素分歧可预测配子兼容性，而（2）同义位点的结合素分歧和线粒体DNA分歧则不能，并且（3）结合素中仅10个氨基酸的变化就能导致物种间完全的配子不兼容性。以线粒体分歧作为时间的替代指标，我们发现完全的配子不兼容性大约可在150万年的时间内进化形成，而姊妹物种可保持完全的配子兼容性长达500万年。
