Collaborative Research: Postmating Reproductive Isolation Among Drosophila arizonae and Drosophila mojavensis

0075307皮特尼克新物种起源的关键事件是生殖隔离的形成。 然而，一个物种如何分裂成两个生殖隔离的生物群体，人们知之甚少。 果蝇属的果蝇一直是物种形成研究的模式系统。 这些研究集中在交配前或合子后的隔离机制，或那些过程，决定是否男性和女性交配，以及是否他们产生可行的和可育的后代，分别。 在物种形成的研究中，受精和卵子受精之间发生的大量事件在很大程度上被忽视了。 然而，最近的研究表明，精子、精液和女性生殖道的特征对成功的生殖至关重要，但它们之间的差异很快。 研究人员假设，这种分歧将导致减少生殖成功时，成员的遗传分化种群杂交，他们提出了一系列的实验，以明确测试这一假设使用D。arizonae及其姊妹种D.莫哈韦西斯，都是北美特有的。 因为D.来自不同地理区域的莫哈韦西斯被认为是初期物种，调查人员将利用自然发生的生殖隔离连续体来测试他们的预测。 初步数据表明，D. mojavensis在待测量的性状上有显著差异。 通过在具有已知生殖特征的不同种群和物种的成员之间进行实验室杂交，研究人员将确定这些特征如何导致对新物种形成至关重要的生殖障碍。 这些实验的结果可能对新物种的形成具有重要意义。

0075307 PitnickThe crucial event for the origin of new species is the formation of reproductive isolation. How one species splits into two reproductively isolated groups of organisms, however, is poorly understood. Fruitflies of the genus Drosophila have been a model system for studies of speciation. These studies have focused on premating or postzygotic isolating mechanisms, or those processes that determine whether or not males and females mate and whether or not they produce viable and fertile offspring, respectively. The multitude of events occurring between insemination and egg fertilization has been largely ignored in studies of speciation. Recent work, however, indicates that sperm, seminal fluid, and female reproductive tract characteristics that are of central importance for successful reproduction are rapidly divergent. The investigators postulate that this divergence will cause diminished reproductive success whenever members of genetically differentiated populations interbreed, and they propose a series of experiments to explicitly test this hypothesis using D. arizonae and its sibling species D. mojavensis, both endemic to North America. Because D. mojavensis from different geographic regions are considered to be incipient species, the investigators will take advantage of a naturally occurring continuum of reproductive isolation for testing their predictions. Preliminary data indicate that populations of D. mojavensis differ significantly in the traits to be measured. By conducting laboratory crosses between members of different populations and species with known reproductive characteristics, the investigators will determine how these characteristics lead to reproductive barriers central to the formation of new species. Results of these experiments may have important implications for the formation of new species.