Drummond Christopher S
Department of Biology, Georgetown University, 406 Reiss Sciences Building, 37th and O Streets, NW, Washington, DC 20057, USA.
Mol Phylogenet Evol. 2008 Aug;48(2):408-21. doi: 10.1016/j.ympev.2008.03.009. Epub 2008 Mar 14.
Previous phylogenetic studies of Lupinus (Leguminosae) based on nuclear DNA have shown that the western New World taxa form a monophyletic group representing the majority of species in the genus, with evidence for high rates of recent diversification in South America following final uplift of the Andes 2-4 million years ago (Mya). For this study, three regions of rapidly evolving non-coding chloroplast DNA (trnL intron, trnS-trnG, and trnT-trnL) were examined to estimate the timing and rates of diversification in the western New World, and to infer ancestral states for geographic range, life history, and maximum elevation. The western New World species (5.0-9.3Mya, 0.6-1.1 spp./My) comprise a basally branching assemblage of annual plants endemic to the lower elevations of western North America, from which two species-rich clades are recently derived: (i) the western North American perennials from the Rocky Mountains, Great Basin, and Pacific Slope (0.7-2.1Mya, 2.0-5.9 spp./My) and (ii) the predominantly perennial species from the Andes Mountains of South America and highlands of Mexico (0.8-3.4Mya, 1.4-5.7spp./My). Bayesian posterior predictive tests for association between life history and maximum elevation demonstrate that perennials are positively correlated with higher elevations. These results are consistent with a series of one or more recent radiations in the western New World, and indicate that rapid diversification of Lupinus coincides with the derived evolution of perennial life history, colonization of montane habitats, and range expansion from North America to South America.
先前基于核DNA对羽扇豆属（豆科）进行的系统发育研究表明，西半球新大陆的分类群形成了一个单系类群，代表了该属中的大多数物种，有证据表明，在200万至400万年前（百万年前）安第斯山脉最终隆升之后，南美洲近期出现了高分化率。在本研究中，对快速进化的非编码叶绿体DNA的三个区域（trnL内含子、trnS-trnG和trnT-trnL）进行了检测，以估计西半球新大陆的分化时间和速率，并推断地理范围、生活史和最高海拔的祖先状态。西半球新大陆的物种（5.0 - 9.3百万年前，0.6 - 1.1种/百万年）包括一个基部分支的一年生植物组合，这些植物是北美西部低海拔地区特有的，最近从中衍生出两个物种丰富的分支：（i）来自落基山脉、大盆地和太平洋沿岸的北美西部多年生植物（0.7 - 2.1百万年前，2.0 - 5.9种/百万年），以及（ii）来自南美洲安第斯山脉和墨西哥高地的主要多年生物种（0.8 - 3.4百万年前，1.4 - 5.7种/百万年）。对生活史与最高海拔之间关联的贝叶斯后验预测检验表明，多年生植物与较高海拔呈正相关。这些结果与西半球新大陆近期一系列一次或多次辐射相一致，并表明羽扇豆属的快速分化与多年生生活史的衍生进化、山地栖息地的定殖以及从北美到南美的范围扩张相吻合。
