Evolution of Reproductive Isolation and Speciation in Neurospora

这项研究的目的是了解当种群分化成不同的物种时，杂交障碍是如何进化的。这个问题将通过研究两个地理上和遗传上分离的神经孢子虫（一种丝状真菌（霉菌），是生物学中研究得最好的生物之一）群体之间的杂交，以及N. crassa与其近亲N. intermedia之间的杂交来解决。这个项目有两个主要目标。首先是识别和测量在整个性途径中操作的生殖隔离的单个组成部分，从杂交父母之间交配相互作用的缺陷到杂交后代的无生存能力。第二个目标是绘制控制生殖隔离障碍的遗传位点，并在不同的生物地理情景下测试关于生殖隔离的进化遗传学假设。生殖隔离的进化是新物种起源的一个关键事件，希望这项研究能增加我们对促进地球生物多样性的基本机制的理解。在神经孢子虫中，正如在许多物种中一样，生殖隔离的强度是地理结构的：对于给定的物种对，来自不同地点的杂交亲本比来自同一地点的杂交亲本更具干扰性。这一观察结果表明，当物种聚集在一起时，地理上孤立的物种之间的基线生殖隔离进化通过反对杂交的自然选择得到加强。这里进行的工作旨在了解这一过程的遗传基础。

The object of the research is to understand how barriers to hybridization evolve as populations diverge into separate species. This problem will be addressed by studying hybrid crosses between two geographically and genetically isolated populations of Neurospora crassa, a filamentous fungus (mold) that is one of the best studied organisms in biology, and between N. crassa and its close relative N. intermedia. This project has two main goals. The first is to identify and measure the individual components of reproductive isolation operating throughout the sexual pathway, from defects in mating interactions between hybridizing parents to inviability of hybrid offspring. The second goal is to map genetic loci controlling reproductive isolation barriers and to test hypotheses about the evolutionary genetics of reproductive isolation under different biogeographic scenarios. The evolution of reproductive isolation is a key event in the origin of new species, and it is hoped that this research will add to our scant understanding of a foundational mechanism that promotes biodiversity on Earth. In Neurospora, as in many species, the intensity of reproductive isolation is geographically structured: for a given species pair, hybridizing parents from disparate locations are more interfertile than hybridizing parents from the same location. This observation suggests that baseline reproductive isolation evolving between geographically isolated species is reinforced by natural selection against hybridization when species occur together. The work undertaken here aims to understand the genetic basis of this process.