Genetic Analysis of an Insect Hybrid Zone

物种形成——新物种产生的过程——仍然是动物多样性研究中最具争议（也最不为人所知）的方面之一。密切相关物种之间的自然杂交事件为研究物种差异的遗传基础和保持物种差异的基因交换障碍的性质提供了独特的机会。通过对杂交带内和杂交带附近基因型分布的分析，可以获得有关导致遗传分离的基因分布和数量的信息。该项目将以高分辨率记录密切相关的昆虫物种之间杂交的一个非常有特征的区域的遗传变异模式。这些遗传分析将与交配前和交配后基因交换障碍（导致生殖隔离的因素）的研究相结合。该项目将利用重组DNA技术鉴定一组限制性片段长度多态性（RFLPs），作为遗传标记来分析杂交和回交的程度和方向，以及等位基因从一个物种流向另一个物种的后果。RFLPs的发现为研究遗传疾病的人类遗传学家提供了一套非常有用的标记，也为其他物种自然种群的遗传研究带来了巨大的希望。在本研究过程中发展的方法和理解将在各种情况下有用。

Speciation - the process through which new species arise - remains one of the most controversial (and poorly understood) aspects of the study of animal diversity. Natural hybridization events between closely related species provide unique opportunities to investigate the genetic basis of species differences and the nature of the barriers to gene exchange that tend to keep species distinct. Information about the distribution and number of genes that contribute to genetic isolation can be gained from analysis of the distribution of genotypes within and adjacent to a hybrid zone. This project will document, at high resolution, patterns of genetic variation in a very well-characterized zone of hybridization between closely related insect species. These genetic analyses will be coupled with studies of both pre-mating and post-mating barriers to gene exchange (factors that cause reproductive isolation). The project will take advantage of recombinant DNA technology to identify a set of restriction fragment length polymorphisms (RFLPs), which will serve as the genetic markers to analyze the extent and direction of hybridization and backcrossing and the consequences for the flow of alleles from one species into the other. The discovery of RFLPs has provided an enormously useful set of markers for human geneticists studying inherited diseases and holds great promise for genetic studies of natural populations of other species as well. The approaches and understanding developed in the course of this study will be useful in a variety of contexts.