Department of Environmental Science, Policy and Management, 130 Mulford Hall, University of California, Berkeley, California 94720-3114, USA.
Evolution. 2012 Sep;66(9):2798-814. doi: 10.1111/j.1558-5646.2012.01643.x. Epub 2012 May 14.
Adaptive radiation involves ecological shifts coupled with isolation of gene pools. However, we know little about what drives the initial stages of divergence. We study a system in which ecological diversification is found within a chronologically well-defined geological matrix to provide insight into this enigmatic phase of radiation. We tested the hypothesis that a period of geographic isolation precedes ecological specialization in an adaptive radiation of host-specialized Hawaiian planthoppers. We examined population structure and history using mitochondrial and multiple independent microsatellite loci in a species whose geographic distribution on the island of Hawaii enabled us to observe the chronology of divergence in its very earliest stages. We found that genetic divergence is associated with geographic features but not different plant hosts and that divergence times are very recent and on the same timescales as the dynamic geology of the island. Our results suggest an important role for geography in the dynamics of the early stages of divergence.
适应辐射涉及生态转变以及基因库的隔离。然而，我们对于是什么驱动了分化的初始阶段知之甚少。我们研究了一个系统，其中生态多样化是在一个时间上明确界定的地质基质内发现的，以便深入了解辐射的这个神秘阶段。我们检验了一个假设，即在适应辐射的宿主特异性夏威夷叶蝉中，地理隔离先于生态特化。我们使用线粒体和多个独立的微卫星基因座来检测种群结构和历史，在夏威夷岛上的地理分布使我们能够观察到其分化的最早阶段的时间顺序。我们发现遗传分化与地理特征有关，而与不同的植物宿主无关，而且分化时间非常近，与岛屿的动态地质时间尺度相同。我们的结果表明，地理在分化的早期阶段的动态中起着重要作用。
