The prevalence of genetic introgression in speciation

摘要 背景：物种间遗传交换的重要性一直是争论的主题 在进化生物学家中。基因组数据表明，基因交换更为普遍， 比以前想象的要多，甚至可能成为适应的来源。 广泛的长期目标：拟议的对自然发生的混合区的研究将利用 在杂交区进行的实验，以找到混合的基因组，然后可以用来解剖 两个最近分化的果蝇物种之间行为特征的遗传学差异。这个目标 补充的目的是促进Heidi Mavengere女士的专业发展。 具体目标：该研究的目标1使用来自杂交区的混合果蝇来绘制基因图谱， 温度偏好的重要生态特征。这种特性是生殖隔离的重要来源 在果蝇物种中。混合物作图提供了一个独特的机会，以确定基因， 这些过程最终导致了生态位的分化。Aim 2将测试基因组预测， 功能遗传学测试，以确认与表型差异相关的等位基因是否导致了 找了 方法：在自然生境中采集果蝇，并进行饲养 在实验室条件下。在过去的几年里，我们改进了测序方法， 还开发了在多种果蝇中产生精确基因敲除的能力。这项建议 利用基因组中渐渗等位基因的鉴定来揭示种间遗传基础， 差异在这些混合物分析中鉴定的基因将用CRISPR进行功能验证。 介导的基因置换。我们的混合作图和基因组编辑的初步结果表明， 有能力执行研究计划。 健康相关性：人类混合物图谱是用于识别 致病基因变异然而，后续的实验，以测试基因的功能相关， 疾病很难在人类身上进行。因此，混合物映射方案从未经过验证 从鉴定与疾病相关的变异的群体水平到功能性 分子遗传水平，表现为表型状态。这项提案将研究涉及的特征， 生态生殖隔离使用混合映射，并将连接从统计推断 通过基因组编辑将基因组学转化为可测量的表型差异。 影响：这项研究的结果将提供第一个广泛的情况下，渗入模式的看法， 物种在自然界中杂交，并将利用这些模式的混合物解剖的遗传基础， 导致生殖隔离的物种之间的行为差异。

ABSTRACT Background: The importance of genetic exchange between species has been a constant subject of debate among evolutionary biologists. Genomic data has demonstrated that gene exchange is much more common than previously thought and might even serve as a source of adaptation. Broad, long-term objective: The proposed study of naturally occurring hybrid zones will leverage the natural experiment that occurs in hybrid zones to find admixed genomes with which then can be used to dissect the genetics of behavioral traits that differ between two recently diverged Drosophila species. The goal of this supplement is to facilitate the professional development of Ms. Heidi Mavengere. Specific aims: Aim 1 of the study uses admixed flies from a hybrid zone to map genes underlying the ecologically important trait of temperature preference. This trait is an important source of reproductive isolation among Drosophila species. Admixture mapping provides a unique opportunity to identify the genes and processes that ultimately have led to divergence in ecological niche. Aim 2 will test genomic predictions using functional genetics tests to confirm whether the alleles associated with the phenotypic difference have caused the change. Method: Fruit flies from the genus Drosophila can be collected in their natural habitat and also maintained under laboratory conditions. In the last few years, we have improved our sequencing approaches and have also developed the ability to generate precise gene knock-outs in multiple species of Drosophila. This proposal leverages the identification of introgressed alleles in the genome to reveal the genetic basis of interspecific differences. The genes identified in these admixture analyses will be functionally validated with CRISPR- mediated gene replacements. Our preliminary results for admixture mapping and genome editing indicate we have the ability to execute the research proposal. Health-relatedness: Admixture mapping in humans is a primary approach used for the identification of disease-causing gene variants. However, follow-up experiments to test the function of genes correlated with disease are difficult to perform in humans. Admixture mapping protocols have therefore never been validated end-to-end from the population level at which variants correlated with disease are identified, to the functional molecular genetic level where the phenotypic state is manifested. This proposal will study traits involved in ecological reproductive isolation using admixture mapping and will connect inferences from statistical genomics to measurable phenotypic differences via genome editing. Impact: The results from this study will provide the first broad view of patterns of introgression in cases where species interbreed in nature, and will leverage those patterns of admixture to dissect the genetic basis of behavioral differences between species that cause reproductive isolation.