Laboratoire de Génétique et Evolution des Populations Végétales, UMR-CNRS 8016, Université des Sciences et Technologies de Lille - Lille 1, France.
Evolution. 2010 Mar 1;64(3):772-84. doi: 10.1111/j.1558-5646.2009.00847.x. Epub 2009 Sep 30.
Gynodioecy, where females co-occur with hermaphrodites, is a relatively common sexual system in plants that is often the result of a genetic conflict between maternally inherited male sterility genes in the mitochondrial genome and the biparentally inherited male fertility restorer genes in the nucleus. Previous models have shown that nuclear-cytoplasmic gynodioecy can be maintained under certain conditions by negative frequency-dependent selection, but the effect of other evolutionary processes such as genetic drift and population subdivision is only partially understood. Here, we investigate the joint effects of frequency-dependent selection, drift, and migration through either pollen or seeds on the maintenance of nuclear-cytoplasmic gynodioecy in a subdivided population. We find that the combination of drift and selection causes the loss of gynodioecy under scenarios that would maintain it under the influence of selection alone, and that both seed and, more surprisingly, pollen flow can maintain the polymorphism. In particular, although pollen flow could not avoid the loss of cytoplasmic polymorphism within demes, it allowed the maintenance of nuclear-cytoplasmic polymorphism at the metapopulation level.
雌雄异株，即雌性与雌雄同体共存，是植物中一种相对常见的性系统，通常是线粒体基因组中母系遗传的雄性不育基因和核中双亲遗传的雄性育性恢复基因之间遗传冲突的结果。先前的模型表明，在某些条件下，核质雌雄异株可以通过负频率依赖性选择得以维持，但遗传漂变和种群分裂等其他进化过程的影响仅部分得到理解。在这里，我们通过花粉或种子的迁移来研究频率依赖性选择、漂变和迁移对分裂种群中核质雌雄异株维持的联合影响。我们发现，在单独选择作用下可以维持雌雄异株的情况下，漂变和选择的组合会导致雌雄异株的丧失，而且种子和更令人惊讶的是花粉流都可以维持多态性。特别是，尽管花粉流不能避免细胞质多态性在小种群内的丧失，但它允许在集合种群水平上维持核质多态性。
