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，新物种就产生了。尽管这种分化发生在许多物种中，但大多数物种并没有经历物种形成。是什么阻止了物种形成过程的发生？在植物Campanulastrum americum中，种群间杂种活力的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后代往往表现出完全康复。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导致他们同时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，以及从双亲遗传叶绿体是否可以使该物种克服由于叶绿体分化而降低的后代生存能力。拟议的工作将通过支持一个新的合作，以学习一种量化叶绿体遗传模式的技术，加强研究生培训。此外，这项工作将允许通过独立研究项目继续培养来自不同背景的本科生。最后，提出的研究将促进我们对新物种如何形成的理解，以及是否改变了细胞器基因组的遗传模式，如叶绿体，可能导致物种形成过程减慢。

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.