Dissertation Research: Evaluating Indirect Estimates of Gene Flow: A Comparative Life History Approach

生物自然种群之间的扩散程度影响着一系列广泛的生物事件，包括物种形成、灭绝和局部适应。扩散的遗传结果，称为基因流动，通常是从基因频率的地理分布推断出来的。然而，这种估计的准确性很难确定。测量散布能力不同的近亲物种的基因流动，可以对这种间接估计进行评估。本文概述了分布在不同空间尺度上的19种水螨的采样制度。这些物种中的大多数在它们的一生中只在水生昆虫的成虫阶段分散一次，而少数则根本不分散。螨类的传播能力可以根据已知的宿主属性和宿主-寄生虫关系进行分类排序。利用同工酶数据对各螨种的遗传种群结构进行分析，并对部分寄主的种群结构进行分析。有关昆虫的数据将提供深入了解寄生虫与寄生虫关联的遗传后果。对于水螨，将统计地评估其扩散与基因流动之间的相关性，并考虑其系统发育关系。由于这些螨虫亲缘关系密切，分布在相似的栖息地，并且它们的扩散潜力很好地了解，因此除了扩散能力之外，它们之间的差异最小。这项研究将是第一次尝试评估一大批共同发生的、密切相关的物种的群体遗传结构。

9423603 HAIRSTON The magnitude of dispersal between natural populations of organisms is known to affect a wide array of biological events, including speciation, extinction, and local adaptation. The genetic consequence of dispersal, termed gene flow, is commonly inferred from the geographic distribution of gene frequencies. However, the accuracy of such estimates is difficult to ascertain. Measuring gene flow in closely related species which vary in dispersal ability allows such indirect estimates to be evaluated. This proposal outlines a sampling regime for 19 species disperse of Arrenurus water mites across a range of spatial scales. The majority of these species disperse only once in their lifetime on the adult stages of aquatic insects, while a few do not disperse at all. Dispersal ability of the mite species can be ranked categorically based on known attributes of the host and the host-parasite relationship. Analyses of genetic population structure will be made for each mite species from allozyme data, as will the population structure of some insect hosts. Data regarding the insects will provide insight into the genetic consequences of the parasitic association to the parasites. For the water mites, correlations between dispersal and gene flow will be assessed statistically, and phylogenetic relationships will be considered. Because these mites are closely related, occur in similar habitats, and their dispersal potential is well understood, differences between them other than dispersal ability are minimized. This study will be the first attempt to assess population genetic structure in a large group of co-occurring, closely related species.