García-Martínez J, Castro J A, Ramón M, Latorre A, Moya A
Departament de Genètica, Facultat de Biología, Universitat de València, 46100 Burjassot, Valencia, Spain.
Genetics. 1998 Jul;149(3):1377-82. doi: 10.1093/genetics/149.3.1377.
The evolution of Drosophila subobscura mitochondrial DNA has been studied in experimental populations, founded with flies from a natural population from Esporles (Majorca, Balearic Islands, Spain). This population, like other European ones, is characterized by the presence of two very common (>96%) mitochondrial haplotypes (called I and II) and rare and endemic haplotypes that appear at very low frequencies. There is no statistical evidence of positive Darwinian selection acting on the mitochondrial DNA variants according to Tajima's neutrality test. Two experimental populations, with one replicate each, were established with flies having a heterogeneous nuclear genetic background, which was representative of the composition of the natural population. Both populations were started with the two most frequent mitochondrial haplotypes, but at different initial frequencies. After 13 to 16 generations, haplotype II reached fixation in three cages and its frequency was 0.89 by generation 25 in the fourth cage. Random drift can be rejected as the force responsible for the observed changes in haplotype frequencies. There is not only statistical evidence of a linear trend favoring a mtDNA (haploid) fitness effect, but also of a significant nonlinear deviation that could be due to a nuclear component.
黑腹果蝇线粒体DNA的进化已在实验种群中进行了研究，这些实验种群由来自西班牙巴利阿里群岛马略卡岛埃斯波列斯的一个自然种群的果蝇建立。与其他欧洲种群一样，这个种群的特征是存在两种非常常见（>96%）的线粒体单倍型（称为I和II）以及出现频率极低的稀有和地方单倍型。根据 Tajima 中性检验，没有统计学证据表明正向达尔文选择作用于线粒体DNA变异。用具有异质核遗传背景的果蝇建立了两个实验种群，每个种群有一个重复样本，该遗传背景代表了自然种群的组成。两个种群都以两种最常见的线粒体单倍型开始，但初始频率不同。经过13至16代后，单倍型II在三个笼子中达到固定，在第四个笼子中到第25代时其频率为0.89。随机漂变可以被排除为导致观察到的单倍型频率变化的原因。不仅有统计学证据表明存在有利于线粒体DNA（单倍体）适应性效应的线性趋势，而且还有可能归因于核成分的显著非线性偏差。
