DISSERTATION RESEARCH: Reproductive Incompatibility by Compensatory Mutations.

维持小规模的种群会导致有害突变的积累，破坏个体的适应性。然而，随后恢复到大的群体规模可能会导致在其他基因座的有益突变的固定，以补偿这些负面影响。这种有利的关联在异交过程中可能被破坏，从而导致杂种的适应性下降，这是形成新物种的第一步。这项研究代表了补偿突变在生殖不相容性进化中的作用的第一个实验测试。利用线虫模型系统C.在线虫中，该项目试图：1）通过敲除关键DNA错配修复基因，在小群体规模下维持，使多个品系经历有害突变积累的制度; 2）通过在大群体规模下积累补偿突变，从而产生品系特异性共适应基因复合体，从而在突变退化品系中启动适应性恢复; 3）测试杂交后代中的适应性降低。 本研究将测试基因座间基因相互作用在生殖不相容性进化中的作用，评估物种形成关键模型的有效性，并对保护管理实践产生影响。

The maintenance of populations at small sizes can lead to the accumulation of deleterious mutations that undermine the fitness of individuals. However, subsequent return to large population size can result in the fixation of beneficial mutations at other loci that compensate for these negative effects. Such an advantageous association can be disrupted during outcrossing, thereby leading to a fitness decline in hybrids and representing a first step in the formation of new species. This research represents the first experimental test of the role of compensatory mutations in the evolution of reproductive incompatibility. Using the nematode model system C. elegans, this project attempts to: 1) subject multiple lines to a regime of deleterious mutation accumulation by maintenance at small population sizes with a knockout of a key DNA mismatch repair gene; 2) initiate fitness recovery in mutationally degraded lines via the accumulation of compensatory mutations under large population sizes, thereby creating line-specific coadapted gene complexes and 3) test for diminished fitness in hybrid progeny. This study will test the role of inter-locus gene interactions in the evolution of reproductive incompatibility, evaluate the validity of a key model of speciation, and have implications for conservation management practices.