Federal Research Centre for Forests (BFW), Department of Genetics, Hauptstrasse 7, A-1140 Vienna, Austria.
Mol Ecol. 2011 Jan;20(1):165-78. doi: 10.1111/j.1365-294X.2010.04931.x. Epub 2010 Nov 18.
Scattered populations of the same tree species in montane forests through Africa have led to speculations on the origins of distributions. Here, we inferred the colonization history of the Afromontane tree Prunus africana using seven chloroplast DNA loci to study 582 individuals from 32 populations sampled in a range-wide survey from across Africa, revealing 22 haplotypes. The predominant haplotype, HT1a, occurred in 13 populations of eastern and southern Africa, while a second common haplotype, HT1m, occurred in populations of western Uganda and western Africa. The high differentiation observed between populations in East Africa was unexpected, with stands in western Uganda belonging with the western African lineage. High genetic differentiation among populations revealed using ordered alleles (N(ST) = 0.840) compared with unordered alleles (G(ST) = 0.735), indicated a clear phylogeographic pattern. Bayesian coalescence modelling suggested that 'east' and 'west' African types likely split early during southward migration of the species, while further more recent splitting events occurred among populations in the East of the continent. The high genetic similarity found between western Uganda and west African populations indicates that a former Afromontane migration corridor may have existed through Equatorial Africa.
在非洲的山地森林中，同种树木的分散种群导致了对分布起源的推测。在这里，我们使用七个叶绿体 DNA 基因座来推断 Afromontane 树种非洲李的殖民历史，对来自非洲各地的 32 个种群的 582 个个体进行了研究，发现了 22 种单倍型。主要的单倍型 HT1a 出现在东非和南非的 13 个种群中，而第二个常见的单倍型 HT1m 出现在乌干达西部和西非的种群中。东非各群体之间观察到的高分化是出乎意料的，乌干达西部的种群与西非谱系有关。使用有序等位基因（N（ST）= 0.840）与无序等位基因（G（ST）= 0.735）相比，各群体之间存在高度的遗传分化，表明存在明显的系统地理模式。贝叶斯聚类模型表明，“东”和“西”非类型可能在该物种向南迁移的早期就已经分裂，而在该大陆东部的种群之间则发生了更近的分裂事件。在乌干达西部和西非种群之间发现的高度遗传相似性表明，以前可能存在一条通过赤道非洲的 Afromontane 迁移走廊。
