Karyotypic diversity and speciation in Agrodiaetus butterflies
Karyotypic diversity and speciation in Agrodiaetus butterflies
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DOI：
10.1111/j.1558-5646.2007.00046.x
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发表时间：
2007-03-01
期刊：
影响因子：
3.3
通讯作者：
Pierce, Naomi E.
中科院分区：
文献类型：
--
作者：
Kandul, Nikolai R.;Lukhtanov, Vladimir A.;Pierce, Naomi E.
染色体重排可能在维持既定物种之间的合子后分离中发挥重要作用，这是物种形成标准理论的一部分。然而，很少有证据表明核型变化在物种形成本身中的作用-在先前杂交种群之间建立生殖障碍。大属“Agrodiaetus”（鳞翅目：Lycaenidae）为研究这一问题提供了一个模式系统。农蝶在染色体数目上表现出不同寻常的种间多样性，从n = 10到n = 134；相比之下，大多数lycaenid蝴蝶的n = 23/24。我们分析了核型多样性的进化通过绘制染色体数目在一个彻底取样的线粒体系统发育属。异域姐妹类群之间的核型差异逐渐积累，而同域姐妹类群之间的核型差异积累得更快。总体而言，同域姐妹类群的平均核型多样性高于异域姐妹类群。分化种群的差异融合可能解释了这种模式，因为异域种群之间获得的核型差异程度可能决定了它们是否会在次生同域中作为新生生物物种持续存在。因此，这项研究发现了在动物物种形成的最后阶段染色体重排的直接作用的证据。快速的核型多样化很可能促成了在Agrodiaetus中观察到的爆炸性物种形成速度，每百万年1.6个物种。
That chromosomal rearrangements may play an important role in maintaining postzygotic isolation between well-established species is part of the standard theory of speciation. However, little evidence exists on the role of karyotypic change in speciation itself-in the establishment of reproductive barriers between previously interbreeding populations. The large genus' Agrodiaetus (Lepidoptera: Lycaenidae) provides a model system to study this question. Agrodiaetus butterflies exhibit unusual interspecific diversity in chromosome number, from n = 10 to n = 134; in contrast, the majority of lycaenid butterflies have n = 23/24. We analyzed the evolution of karyotypic diversity by mapping chromosome numbers on a thoroughly sampled mitochondrial phylogeny of the genus. Karyotypic differences accumulate gradually between allopatric sister taxa, but more rapidly between sympatric sister taxa. Overall, sympatric sister taxa have a higher average karyotypic diversity than allopatric sister taxa. Differential fusion of diverged populations may account for this pattern because the degree of karyotypic difference acquired between allopatric populations may determine whether they will persist as nascent biological species in secondary sympatry. This study therefore finds evidence of a direct role for chromosomal rearrangements in the final stages of animal speciation. Rapid karyotypic diversification is likely to have contributed to the explosive speciation rate observed in Agrodiaetus, 1.6 species per million years.