Lamelza Piero, Ailion Michael
Molecular and Cellular Biology Program, University of Washington, Seattle, Washington 98195.
Department of Biochemistry, University of Washington, Seattle, Washington 98195.
G3 (Bethesda). 2017 Mar 10;7(3):823-834. doi: 10.1534/g3.116.037101.
How species arise is a fundamental question in biology. Species can be defined as populations of interbreeding individuals that are reproductively isolated from other such populations. Therefore, understanding how reproductive barriers evolve between populations is essential for understanding the process of speciation. Hybrid incompatibility (for example, hybrid sterility or lethality) is a common and strong reproductive barrier in nature. Here we report a lethal incompatibility between two wild isolates of the nematode Hybrid inviability results from the incompatibility between a maternally inherited cytoplasmic factor from each strain and a recessive nuclear locus from the other. We have excluded the possibility that maternally inherited endosymbiotic bacteria cause the incompatibility by treating both strains with tetracycline and show that hybrid death is unaffected. Furthermore, cytoplasmic-nuclear incompatibility commonly occurs between other wild isolates, indicating that this is a significant reproductive barrier within We hypothesize that the maternally inherited cytoplasmic factor is the mitochondrial genome and that mitochondrial dysfunction underlies hybrid death. This system has the potential to shed light on the dynamics of divergent mitochondrial-nuclear coevolution and its role in promoting speciation.
物种如何形成是生物学中的一个基本问题。物种可定义为能够相互交配繁殖、且与其他此类群体存在生殖隔离的群体。因此，理解群体间生殖屏障如何演化对于理解物种形成过程至关重要。杂种不亲和性（例如，杂种不育或致死）是自然界中常见且强大的生殖屏障。在此，我们报告了线虫两个野生分离株之间的致死性不亲和性。杂种 inviability 是由于每个菌株中母系遗传的细胞质因子与另一个菌株中的隐性核基因座之间的不亲和性所致。我们通过用四环素处理两个菌株排除了母系遗传的内共生细菌导致不亲和性的可能性，并表明杂种死亡不受影响。此外，细胞质 - 核不亲和性在其他野生分离株之间普遍存在，表明这是 内的一个重要生殖屏障。我们假设母系遗传的细胞质因子是线粒体基因组，并且线粒体功能障碍是杂种死亡的基础。该系统有可能揭示线粒体 - 核协同进化分歧的动态及其在促进物种形成中的作用。
