Recent speciation of Capsella rubella from Capsella grandiflora, associated with loss of self-incompatibility and an extreme bottleneck
Recent speciation of Capsella rubella from Capsella grandiflora, associated with loss of self-incompatibility and an extreme bottleneck
复制标题
DOI：
10.1073/pnas.0808012106
复制
发表时间：
2009-03-31
影响因子：
11.1
通讯作者：
Schierup, Mikkel H.
中科院分区：
文献类型：
--
作者：
Guo, Ya-Long;Bechsgaard, Jesper S.;Schierup, Mikkel H.
开花植物通常通过自交不亲和性（S.I.）的机制来防止自交。失去S. I。这种现象多次独立发生，因为它在传粉者或配偶稀少的情况下提供了短期优势。与拟南芥属亲缘关系较近的荠菜属中，存在一对近缘的二倍体种，即自交不亲和的大花荠菜和自交亲和的微红荠菜。为了阐明向自交的转化及其与物种形成的关系。风疹，我们利用了比较序列信息。结果表明，风疹克氏杆菌与风疹克氏杆菌是分离的。grandiflora最近（大约30，000 - 50，000年前）和S.I.几乎是同时发生的。通过比较两种藻的核磷脂多样性，发现C.风疹在大多数位点上只有1或2个等位基因，表明它起源于一个极端的人口瓶颈。我们的数据是一致的二倍体物种由一个单一的，自交的个人，最有可能生活在希腊。新物种随后通过北方和南方路线殖民地中海，同时也看到了农业的传播。现代C.风疹表明，这个物种将是一个有趣的模型，以了解分歧和适应，从非常有限的常设遗传变异。
Flowering plants often prevent selfing through mechanisms of self-incompatibility (S.I.). The loss of S.I. has occurred many times independently, because it provides short-term advantages in situations where pollinators or mates are rare. The genus Capsella, which is closely related to Arabidopsis, contains a pair of closely related diploid species, the self-incompatible Capsella grandiflora and the self-compatible Capsella rubella. To elucidate the transition to selfing and its relationship to speciation of C. rubella, we have made use of comparative sequence information. Our analyses indicate that C rubella separated from C. grandiflora recently (approximate to 30,000-50,000 years ago) and that breakdown of S.I. occurred at approximately the same time. Contrasting the nuclecitide diversity patterns of the 2 species, we found that C. rubella has only 1 or 2 alleles at most loci, suggesting that it originated through an extreme population bottleneck. Our data are consistent with diploid speciation by a single, selfing individual, most likely living in Greece. The new species subsequently colonized the Mediterranean by Northern and Southern routes, at a time that also saw the spread of agriculture. The presence of phenotypic diversity within modern C. rubella suggests that this species will be an interesting model to understand divergence and adaptation, starting from very limited standing genetic variation.