Lorenzen Eline D, Arctander Peter, Siegismund Hans R
Department of Evolutionary Biology, Institute of Biology, University of Copenhagen, Universitetsparken 15, DK-2100 Copenhagen Ø, Denmark.
J Hered. 2006 Mar-Apr;97(2):119-32. doi: 10.1093/jhered/esj012. Epub 2006 Jan 11.
Samples of 162 impala antelope (Aepyceros melampus) from throughout its distribution range in sub-Saharan Africa were surveyed using eight polymorphic microsatellite loci. Furthermore, 155 previously published mitochondrial DNA (mtDNA) sequences from the same localities were reanalyzed. Two subspecies of impala are presently recognized--the isolated black-faced impala (Aepyceros melampus petersi) in southwest Africa and the common impala (Aepyceros melampus melampus) abundant in southern and east Africa. All tests performed indicated significant genetic differentiation at the subspecific level. Furthermore, individual-based analyses split the common impala subspecies into two distinct genetic groups, conforming with regional geographic affiliation to southern or east Africa. This was supported by assignment tests, genetic distance measures, pairwise theta values, and analysis of molecular variance. We suggest that the presence of such previously unknown regional structuring within the subspecies reflects a pattern of colonization from a formerly large panmictic population in southern Africa toward east Africa. This scenario was supported by a progressive decline in population diversity indices toward east Africa and a significant increase in the quantity theta/(1 - theta). Both microsatellite and mtDNA data indicated a genetic distinctiveness of the Samburu population in Kenya.
利用8个多态微卫星位点对来自撒哈拉以南非洲整个分布范围内的162只黑斑羚（Aepyceros melampus）样本进行了调查。此外，还重新分析了来自相同地点的155个先前发表的线粒体DNA（mtDNA）序列。目前已确认黑斑羚有两个亚种——非洲西南部孤立的黑脸黑斑羚（Aepyceros melampus petersi）和在南部和东部非洲数量众多的普通黑斑羚（Aepyceros melampus melampus）。所有进行的测试均表明在亚种水平上存在显著的遗传分化。此外，基于个体的分析将普通黑斑羚亚种分为两个不同的遗传群体，这与它们在南部或东部非洲的区域地理归属一致。这得到了赋值测试、遗传距离测量、成对θ值和分子方差分析的支持。我们认为，亚种内这种先前未知的区域结构的存在反映了从南部非洲一个曾经庞大的随机交配种群向东非的殖民模式。这种情况得到了向东部非洲种群多样性指数逐渐下降以及θ/（1 - θ）数量显著增加的支持。微卫星和mtDNA数据均表明肯尼亚桑布鲁种群具有遗传独特性。
