Evidence for non-neutrality of mitochondrial DNA haplotypes in Drosophila pseudoobscura.
Evidence for non-neutrality of mitochondrial DNA haplotypes in Drosophila pseudoobscura.
复制标题
DOI：
10.1093/genetics/120.2.485
复制
发表时间：
1988-10
期刊：
影响因子：
3.3
通讯作者：
Amy F. MacRae;Wyatt W. Anderson
中科院分区：
文献类型：
--
作者：
Amy F. MacRae;Wyatt W. Anderson
线粒体DNA(MtDNA)单倍型通常被认为是进化中的女性血统的中性、未经选择的标记。通过监测线粒体DNA单倍型多态的12个实验种群的单倍型频率，验证了这一假设。种群至少维持了10代，在一种情况下维持了32代，同时进行了线粒体DNA选择性中性测试。在由两个线粒体单倍型不同的菌株混合而成的初始群体中，波哥大单倍型的频率在3代中增加了46%，32代后达到表观平衡频率82%。通过添加不太常见的单倍型来扰乱这一平衡，导致第二单倍型的频率迅速、戏剧性地增加，并返回到基本上与扰动前相同的平衡频率。这种行为不符合mtDNA的中性，平衡也不符合单倍体mtDNA的恒定选择的简单模型。线粒体DNA单倍型的重复笼式实验并不总是产生与初始笼式相同的结果。一些证据，包括对核基因组的操纵，支持核基因组和线粒体基因组都与线粒体DNA频率的戏剧性变化有关的观点。在另一项实验中，通过mtDNA频率的变化，可以发现强烈的雌性生存能力选择。虽然线粒体DNA频率在我们的种群中戏剧性变化的原因并不明显，但很明显，果蝇线粒体单倍型并不总是简单的中性标记。我们的发现与将一种新的线粒体DNA变异从一个物种或一个种群引入另一个物种或另一个种群有关。这样的介绍可能会受到选择的强烈欢迎，即使它是零星的。
Mitochondrial DNA (mtDNA) haplotypes usually are assumed to be neutral, unselected markers of evolving female lineages. This assumption was tested by monitoring haplotype frequencies in 12 experimental populations of Drosophila pseudoobscura which were polymorphic for mtDNA haplotypes. Populations were maintained for at least 10 generations, and in one case for 32 generations, while tests of mtDNA selective neutrality were conducted. In an initial population, formed from a mixture of two strains with different mitochondrial haplotypes, the frequency of the Bogota haplotype increased 46% in 3 generations, reaching an apparent equilibrium frequency of 82% after 32 generations. Perturbation of this equilibrium by addition of the less common haplotype resulted in a rapid, dramatic increase in frequency of the second haplotype, and a return to essentially the same equilibrium frequency as before perturbation. This behavior is not consistent with mtDNA neutrality, nor is the equilibrium consistent with a simple model of constant selection on the haploid mtDNAs. Replicate cage experiments with mtDNA haplotypes did not always generate the same result as the initial cage. Several lines of evidence, including manipulations of the nuclear genome, support the idea that both nuclear and mitochondrial genomes are involved in the dramatic mtDNA frequency changes. In another experiment, strong female viability selection was implicated via mtDNA frequency changes. Although the causes of the dramatic mtDNA frequency changes in our populations are not obvious, it is clear that Drosophila mitochondrial haplotypes are not always simply neutral markers. Our findings are relevant to the introduction of a novel mtDNA variant from one species or one population into another. Such introductions could be strongly favored by selection, even if it is sporadic.