Terai Yohey, Mayer Werner E, Klein Jan, Tichy Herbert, Okada Norihiro
Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama 226-8501, Japan.
Proc Natl Acad Sci U S A. 2002 Nov 26;99(24):15501-6. doi: 10.1073/pnas.232561099. Epub 2002 Nov 15.
In East African Lake Victoria >200 endemic species of haplochromine fishes have been described on the basis of morphological and behavioral differences. Yet molecular analysis has failed to reveal any species-specific differences among these fishes in either mitochondrial or nuclear genes. Although the genes could be shown to vary, the variations represent trans-species polymorphisms not yet assorted along species lines. Nevertheless, fixed genetic differences must exist between the species at loci responsible for the adaptive characters distinguishing the various forms from one another. Here we describe variation and fixation at the long wavelength-sensitive (LWS) opsin locus, which is selection-driven, adaptive, and if not species- then at least population-specific. Because color is one of the characters distinguishing species of haplochromine fishes and color perception plays an important part in food acquisition and mate choice, we suggest that the observed variation and fixation at the LWS opsin locus may have been involved in the process that has led to the spectacular species divergence of haplochromine fishes in Lake Victoria.
在东非维多利亚湖，已根据形态和行为差异描述了200多种丽鱼科丽鱼属的特有物种。然而，分子分析未能揭示这些鱼类在线粒体基因或核基因上存在任何物种特异性差异。尽管可以证明基因存在变异，但这些变异代表的是尚未按物种谱系分类的跨物种多态性。然而，在负责区分各种形态的适应性特征的基因座上，物种之间必然存在固定的遗传差异。在此，我们描述了长波长敏感（LWS）视蛋白基因座的变异和固定情况，该基因座受选择驱动、具有适应性，即便不是物种特异性的，至少也是种群特异性的。由于颜色是区分丽鱼科丽鱼属物种的特征之一，且颜色感知在食物获取和配偶选择中起着重要作用，我们认为在LWS视蛋白基因座上观察到的变异和固定可能参与了导致维多利亚湖丽鱼科鱼类惊人物种分化的过程。
