The genetic basis of prezygotic isolation between species

新物种的形成产生了我们今天看到的广泛的生物多样性，但对物种隔离的潜在遗传基础知之甚少。特别是，没有发现行为隔离的基因，这被认为是第一个物种障碍。我的研究计划已经确定了行为隔离的前三个基因。拟议的研究将以四种方式表征物种特异性雌性偏好行为的基因：（1）我们将使用果蝇中强大的Gal 4-UAS系统来识别大脑中受这三种基因影响的细胞亚群，从而引起雌性偏好和隔离行为。(2)我们将使用转基因技术来确定这三个基因中每一个的精确核苷酸，这些基因是行为隔离的基础，以及这些基因是通过编码序列（蛋白质差异）还是调控序列（表达水平差异）起作用。(3)我们将在每个物种的多个种群中评估这些基因，以确定这三个基因座如何在物种内和物种间的行为作出贡献的进化背景。(4)我们将继续绘制和执行个别候选基因的测试，以确定更多的行为隔离位点。这项工作将大大增加我们对交配行为的复杂特征的遗传和神经基础的理解，并使我们能够确定行为成为物种之间区分机制的机制。通过在物种隔离的背景下进行这些研究，我们也可以开始解决有关其基础的基本问题：相关基因的数量和细胞学位置，它们的进化速度，它们对隔离的相对影响，以及特定的遗传或神经通路是否更经常参与，仅举几例。

The formation of new species gives rise to the wide array of biodiversity we see today, yet very little is known about the underlying genetic basis of species isolation. In particular, no genes have been identified for behavioural isolation, which is thought to be the first species barrier to arise. My research program has identified the first three genes for behavioural isolation. The proposed research will characterize genes for species-specific female preference behaviour in four ways: (1) We will use the powerful Gal4-UAS system in Drosophila to identify the subset(s) of cells within the brain that are affected by these three genes, giving rise to female preference and isolation behaviours. (2) We will use transgenics to identify the precise nucleotides within each of these three genes that underlie behavioural isolation and whether these genes act via coding sequence (protein differences) or regulatory sequence (expression level differences). (3) We will evaluate these genes in multiple populations within each species in order to identify the evolutionary context of how these three loci contribute to behaviour within and between species. (4) We will continue mapping and performing tests of individual candidate genes order to identify additional behavioural isolation loci. This work will significantly add to our understanding of the genetic and neural basis of the complex trait of mating behaviour and allow us to identify the mechanism by which behaviour becomes a discriminating mechanism between species. By performing these studies in the context of species isolation, we can also begin to address fundamental questions regarding its underpinnings: the number and cytological location of the genes involved, their rate of evolution, their relative effect on isolation, and whether particular genetic or neurological pathways are more often involved, to name a few.