DISSERTATION RESEARCH: Within species reproductive isolation: does chloroplast inheritance mediate cytonuclear incompatibility?

当一个物种内的种群分化，不再能够产生可行的杂交后代时，就会出现新的物种。然而，尽管在许多物种中出现了这种差异，但大多数物种并没有经历物种形成。是什么阻止了这种物种形成过程的发生？在植物种类中，美洲风铃草种群间杂交种的活力降低与叶绿体基因组的分化有关。然而，这些表现不佳的杂交种的后代通常会完全康复。叶绿体和线粒体基因组通常只从母亲那里遗传。然而，不同种群之间的杂交可能会导致它们从母亲和父亲那里遗传。该项目将测试叶绿体的遗传模式是否受到杂交的影响，以及从双亲那里继承叶绿体是否允许该物种克服由于叶绿体分化而导致的后代活力下降。拟议的工作将通过支持一项新的合作来加强研究生培训，目的是学习量化叶绿体遗传模式的技术。此外，这项工作将允许通过独立研究项目继续培训来自不同背景的本科生。最后，拟议的研究将促进我们对新物种是如何形成的，以及细胞器基因组(如叶绿体)遗传模式的改变是否会导致物种形成过程放缓的理解。

New species arise as populations within a species become differentiated and are no longer able to produce viable hybrid offspring. Even though such divergence occurs in many species, however, most do not undergo speciation. What prevents this speciation process from occurring? In the plant species Campanulastrum americanum reduced viability of between-populations hybrids is correlated with divergence in the chloroplast genome. Offspring of these low performing hybrids, though, often show complete recovery. Chloroplast and mitochondria genomes are typically inherited only from the mother. However, hybridization between divergent populations may lead to their inheritance from both the mother and father. This project will test whether inheritance patterns of the chloroplast are affected by hybridization, and if inheriting the chloroplast from both parents allows this species to overcome reduced offspring viability due to chloroplast divergence. The proposed work will enhance graduate training by supporting a new collaboration for the purpose of learning a technique for quantifying chloroplast inheritance patterns. In addition, this work will allow for the continued training of undergraduate students from diverse backgrounds through independent research projects. Finally, the proposed research will advance our understanding of how new species form, and whether altered inheritance patterns of the organelle genomes, such as the chloroplast, may result in slowing the speciation process.