The Molecular Basis of Coadaptation and Hybrid Breakdown

当动物或植物从遗传上不同的群体杂交，所产生的杂种往往表现出降低性能（杂交故障）相对于他们的父母。 这在第二代（F2）杂种中尤其如此，其中不相容的基因型可能通过重组产生。 拟议的工作使用海洋桡足类Tigriopus californicus作为模型系统的杂交故障的分子机制进行分析。 这个项目有两个部分。 首先，实验集中在核和线粒体基因之间的相互作用，测试杂交破坏线粒体能量产生的假设。 该研究的第二部分测试了杂交破坏rRNA基因转录的假设，这导致杂交种蛋白质合成速率降低（和性能降低）。 杂种的破坏在自然界中很普遍，在医学、农业和保护生物学中有重要的影响。 该项目的结果可能有助于理解：（1）已知越来越多的人类疾病与破坏线粒体功能的线粒体DNA和核基因突变有关，（2）基因相互作用在农业中的作用，其中强有力的F1杂交菌株通常产生表现较差的F2杂交菌株，以及（3）野生动物管理和保护措施应在多大程度上限制生物体在地理区域之间的移动。该项目还将为本科生、研究生和博士后研究人员提供极好的培训机会。

When animals or plants from genetically divergent populations interbreed, the resulting hybrids often show reduced performance (hybrid breakdown) relative to their parents. This is especially true in second generation (F2) hybrids, where incompatible genotypes may arise via recombination. The proposed work uses the marine copepod Tigriopus californicus as a model system for analyses of the molecular mechanisms underlying hybrid breakdown. This project has two parts. In the first, experiments focus on interactions between nuclear and mitochondrial genes, testing the hypothesis that hybridization disrupts energy production in mitochondria. The second part of the study tests the hypothesis that hybridization disrupts transcription of rRNA genes and this results in reduced rates of protein synthesis (and reduced performance) in hybrids. Hybrid breakdown is widespread in nature and has important ramifications in medicine, agriculture and conservation biology. Results from this project may aid in understanding: (1) the growing number of human diseases known to be associated with mtDNA and nuclear gene mutations which disrupt mitochondrial function, (2) the role of gene interactions in agriculture, where vigorous F1 hybrid strains often give rise to poor-performing F2 hybrids, and (3) the extent to which wildlife management and conservation practices should restrict movement of organisms among geographic locales. The project will also provide excellent training opportunities for undergraduate, graduate and postdoctoral researchers.