Begun D J, Aquadro C F
Cornell University, Section of Genetics and Development, Ithaca, New York 14853.
Nature. 1993 Oct 7;365(6446):548-50. doi: 10.1038/365548a0.
Understanding genetic evolution within species requires an accurate description of variation within and between populations and the ability to distinguish between the potential causes of an observed distribution of variation. In the cosmopolitan species Drosophila melanogaster, previous studies suggested that gene flow within and between continents is extensive and that most of the nuclear gene variation is found within, rather than among, populations. Here we present evidence that a population from Zimbabwe is more than twice as variable as those from the United States of America at the DNA sequence level, that most variants are not shared between the two geographic regions, and that there are nearly fixed differences between the Zimbabwe and USA samples in genomic regions experiencing low recombination rates. It appears that there is an unappreciated degree of population structure in D. melanogaster and that equilibrium models of molecular evolution are inappropriate for this species.
了解物种内部的遗传进化需要准确描述种群内部和种群之间的变异，并能够区分观察到的变异分布的潜在原因。在世界性物种黑腹果蝇中，先前的研究表明，各大洲内部和之间的基因流动广泛，并且大多数核基因变异存在于种群内部而非种群之间。在这里，我们提供的证据表明，在DNA序列水平上，来自津巴布韦的一个种群的变异程度是来自美国的种群的两倍多，这两个地理区域之间的大多数变异并不共享，并且在重组率较低的基因组区域中，津巴布韦和美国样本之间存在近乎固定的差异。看来黑腹果蝇的种群结构程度未被充分认识，分子进化的平衡模型不适用于该物种。
