Hale L R, Singh R S
Department of Biology, McMaster University, Hamilton, Ontario, Canada.
Mol Biol Evol. 1987 Nov;4(6):622-37. doi: 10.1093/oxfordjournals.molbev.a040466.
The understanding of the genetic structure of a species can be improved by considering together data from different types of genetic markers. In the past, a number of worldwide populations of Drosophila melanogaster have been extensively studied for several such markers, including allozymes, chromosomal inversions, and quantitative characters. Here we present results from a study of restriction-fragment-length polymorphisms of mitochondrial DNA (mtDNA) in 92 isofemale lines from many of the same geographic populations of D. melanogaster. Eleven restriction enzymes were used, of which four revealed restriction-site polymorphism. A total of 24 different haplotypes were observed, of which 18 were unique to single populations. In many populations, the unique haplotypes have reached high frequency without being observed in neighboring populations. A Wagner parsimony tree reveals that mutationally close variants show geographical clumping, suggesting local differentiation of mtDNA in populations. The Old-World and the New-World populations are differentiated, with the predominant Old-World haplotype being virtually absent from the New World. These results contrast with those for the nuclear genes, in which many loci show parallel clines in different continents, and suggest a common origin of D. melanogaster populations in North America.
通过综合考虑来自不同类型遗传标记的数据，可以增进对一个物种遗传结构的理解。过去，已经对许多全球范围内的黑腹果蝇种群进行了广泛研究，涉及多种此类标记，包括等位酶、染色体倒位和数量性状。在此，我们展示了一项针对来自许多相同地理种群的92个同雌系黑腹果蝇线粒体DNA（mtDNA）限制性片段长度多态性的研究结果。使用了11种限制性酶，其中4种显示出限制性位点多态性。总共观察到24种不同的单倍型，其中18种是单个种群所特有的。在许多种群中，这些独特的单倍型在相邻种群中未被观察到的情况下达到了高频。一棵瓦格纳简约树显示，突变相近的变体呈现地理聚集，表明种群中mtDNA的局部分化。旧世界和新世界的种群存在差异，新世界几乎不存在占主导地位的旧世界单倍型。这些结果与核基因的结果形成对比，核基因中的许多位点在不同大陆呈现平行渐变群，并表明北美黑腹果蝇种群有共同的起源。
