DNA Variability and Genetic Hitchhiking in Mus

小行星9306493 群体遗传学的一个中心目标是了解生物体自然群体中形成遗传变异的过程。 一个重要的现象，被称为遗传搭便车，涉及自然选择和遗传重组（一个基因的两个拷贝之间的遗传混合）的相互作用。 当特定的DNA突变受到自然选择的青睐时，它可能会在种群中变得更加常见，因为具有该突变的个体将取代没有该突变的个体。然而，当自然选择青睐特定的DNA位点时，它也会影响附近本身不受选择的DNA位点。 通常情况下，基因搭便车将导致这些附近位点的DNA变异性减少。 还原的量取决于复合的速率。 这种关系很重要，因为它使我们能够通过比较具有不同重组率的基因的DNA变异水平来寻找自然选择的证据。 最近对果蝇（果蝇）的研究表明，遗传搭便车可能会影响大部分基因组。 这对基因组进化具有广泛的意义，包括暗示自然选择可能相当频繁地起作用。 为了了解这些发现是否代表了分子进化的一般方面，这项研究将寻找家鼠Mus arteriticus遗传搭便车的证据。 这将通过比较X染色体上四个重要基因之间的DNA序列变异水平来实现：两个具有高重组率（Pip和Amg），两个具有较低重组率（Hprt和G6 pd）。 如果遗传搭便车是常见的，那么具有高重组率的两个基因应该比具有低重组率的两个基因显示出更大的DNA序列变异性。 小鼠中这四种基因中的三种作为人类遗传性疾病的重要模型（Hprt：莱-尼二氏综合征; G6 pd：溶血性贫血; Plp：埃-梅二氏病）。

9306493 Nachman A central goal of population genetics is to understand the process that shape genetic variation in natural populations of organisms. An important phenomenon, knows as genetic hitchhiking, involves the interaction of natural selection and genetic recombination (genetic mixing between the two copies of a gene). When a particular DNA mutation is favored by natural selection, it may become more common in a population since individuals with the mutation will replace individuals without it. However, when natural selection favors a particular DNA site, it will also affect nearby DNA sites which are not themselves under selection. Typically, genetic hitchhiking will cause a reduction in DNA variability at these nearby sites. The amount of reduction depends on the rate of recombination. This relationship is important because it allows us to look for evidence of natural selection by comparing levels of DNA variability in genes with different recombination rates. Recent studies on fruit flies (Drosophila) have demonstrated that genetic hitchhiking may affect a large portion of the genome. This has broad significance for genome evolution, including the implication that natural selection may be acting quite frequently.%%% To learn if these findings represent a general aspect of molecular evolution, this study will look for evidence of genetic hitchhiking in the house mouse, Mus domesticus. This will be achieved by comparing levels of DNA sequence variation among four important genes on the X-chromosome: two with high recombination rates (Pip and Amg), and two with lower recombination rates (Hprt and G6pd). If genetic hitchhiking is common, then the two genes with a high recombination rate should show a greater amount of DNA sequence variability than the two genes with a low recombination rate. Three of these four genes in mice serve as important models for human genetic diseases (Hprt: Lesch-Nyhan syndrome; G6pd: hemolytic anemia: Plp: P elizaeus-Merzbacher disease).