Global Population Genetic Structure of Caenorhabditis remanei Reveals Incipient Speciation
Global Population Genetic Structure of Caenorhabditis remanei Reveals Incipient Speciation
复制标题
雷马尼秀丽隐杆线虫全球群体遗传结构揭示了早期物种形成
DOI：
10.1534/genetics.112.140418
复制
发表时间：
2012-08-01
期刊：
影响因子：
3.3
通讯作者：
Cutter, Asher D.
中科院分区：
文献类型：
--
作者：
Dey, Alivia;Jeon, Yong;Cutter, Asher D.
交配系统的转变极大地改变了基因组的进化轨迹，这可以通过具有不同繁殖模式的物种的对比来揭示。对于小杆线虫中的这种转变，已经识别出自交物种中基因组变异的一些主要原因。然而，我们只有有限的了解，其异交亲属，代表了自交物种的祖先繁殖状态的物种范围内的群体遗传过程。多位点多种群序列多态性数据提供了一种强有力的手段来揭示历史人口和进化过程中的形状基因组。在这里，我们调查了三个群体的异交线虫的X染色体上的核苷酸多态性，并证明了它的分歧，从第四个群体描述了一个密切相关的新物种，从中国，C。sp. 23.我们在全球范围内和每个当地人口样本中发现了高遗传变异。尽管欧洲和北美之间存在地理障碍和适度的遗传分化，但相当多的基因流动将C。remanei populations.我们发现了C。sp.23，并对C. remanei，观察到生殖隔离的强烈遗传分化特征，这被种间杂交中大量的F-2杂种破坏所证实。梭sp. 23代表一个不同的生物物种，这提供了一个警示性的例子，说明标准做法如何无法在这一群体中进行物种身份的交配测试。这一物种对允许充分应用的分歧群体遗传学方法专性异交种的小杆线虫，也提出了一个新的焦点审问的遗传和进化的物种与小杆线虫模型系统。
Mating system transitions dramatically alter the evolutionary trajectories of genomes that can be revealed by contrasts of species with disparate modes of reproduction. For such transitions in Caenorhabditis nematodes, some major causes of genome variation in selfing species have been discerned. And yet, we have only limited understanding of species-wide population genetic processes for their outcrossing relatives, which represent the reproductive state of the progenitors of selfing species. Multilocus-multipopulation sequence polymorphism data provide a powerful means to uncover the historical demography and evolutionary processes that shape genomes. Here we survey nucleotide polymorphism across the X chromosome for three populations of the outcrossing nematode Caenorhabditis remanei and demonstrate its divergence from a fourth population describing a closely related new species from China, C. sp. 23. We find high genetic variation globally and within each local population sample. Despite geographic barriers and moderate genetic differentiation between Europe and North America, considerable gene flow connects C. remanei populations. We discovered C. sp. 23 while investigating C. remanei, observing strong genetic differentiation characteristic of reproductive isolation that was confirmed by substantial F-2 hybrid breakdown in interspecific crosses. That C. sp. 23 represents a distinct biological species provides a cautionary example of how standard practice can fail for mating tests of species identity in this group. This species pair permits full application of divergence population genetic methods to obligately outcrossing species of Caenorhabditis and also presents a new focus for interrogation of the genetics and evolution of speciation with the Caenorhabditis model system.