The role of geography in adaptive radiation

Although the importance of biogeography in the speciation process is well-recognized, the fundamental role of geographic diversification during adaptive radiations has not been studied to determine its importance during the adaptive radiation process. We examined the relationship between lineage and regional diversification patterns in the South American rodent subfamily Sigmodontinae, one of the best candidates for an adaptive radiation in mammals, to propose a conceptual framework for geographic transitions during adaptive radiations. We reconstructed a time-calibrated phylogeny from four nuclear and one mitochondrial gene for 77% of sigmodontine diversity. Historical biogeography was reconstructed among 14 regions, to which we applied a sliding-window approach to estimate regional transition rates through time. We compared these rate patterns and measured whether regions consisted of species that were more phylogenetically related than expected by chance. Following the initial S...尽管生物地理学（biogeography）在物种形成过程中的重要性已得到广泛认可，但适应辐射（adaptive radiation）进程中地理分化的核心作用，尚未有研究针对其在适应辐射进程中的重要性展开系统探究。本研究以哺乳动物适应辐射的最优候选类群之一——南美啮齿类西啮鼠亚科（Sigmodontinae）为研究对象，探讨支系（lineage）与区域分化模式之间的关联，旨在提出适应辐射过程中地理转变的概念框架。本研究基于4个核基因与1个线粒体基因的数据，为77%的西啮鼠亚科类群重建了时间校准的系统发育树（time-calibrated phylogeny）。本研究在14个区域范围内重建了历史生物地理学（historical biogeography）格局，并采用滑动窗口法（sliding-window approach）估算不同时段的区域转变速率。我们对上述速率模式进行了比较，并检验各区域内的物种是否较随机预期具有更高的系统发育亲缘关系。在初始的S……