Deep genetic divergences among morphologically similar and parapatric Skistodiaptomus (Copepoda: Calanoida: Diaptomidae) challenge the hypothesis of Pleistocene speciation
Deep genetic divergences among morphologically similar and parapatric Skistodiaptomus (Copepoda: Calanoida: Diaptomidae) challenge the hypothesis of Pleistocene speciation
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形态相似的近亲 Skistodiaptomus（桡足类：Calanoida：Diaptomidae）之间的深刻遗传差异挑战了更新世物种形成的假说
DOI：
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发表时间：
2008
期刊：
影响因子：
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通讯作者：
R. Harrison
中科院分区：
文献类型：
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作者：
R. Thum;R. Harrison
我们利用线粒体[细胞色素c氧化酶亚基I (CO I)，细胞色素b和16S]和核[内部转录间隔（ITS）]系统发育来验证该属的更新世分化和物种形成假说。线粒体（mt）DNA序列的差异不支持更新世物种形成的假设，而是表明在属中发生了更古老的物种形成事件。oregonensis和pygmaeus Skistodiaptomus（即两个形态相似且相似的物种）的未校正mtDNA序列差异超过20%。同样地，我们鉴定出了白斑Skistodiaptomus pallidus的三个不同分支，它们的mtDNA序列差异超过15%，这表明甚至在更新世之前，这种形态物种之间的种内差异也存在。我们在S. pygmaeus中发现了CO I假基因的明显证据，但它们的存在并没有导致该基因序列差异的显著高估。取代饱和和强烈的净化选择很可能低估了裂趾龙的序列分化和分化时间。在遗传分化的桡足动物群体中，形态停滞现象的普遍存在表明，物种形成往往发生在很少或没有形态变化的情况下。相反，形态进化可能在物种形成后特殊地发生，并产生形态相似性、共同祖先和分化时间的不一致模式。因此，隐种复合体在桡足类动物中很常见，形态学的物种概念低估了它们真正的物种多样性。©2009 The Linnean Society of London, Biological Journal of Linnean Society, 2009, 96, 150‐165。其他关键词：隐物种-生殖器-内在不相容-分子钟-分子系统发育-形态停滞-多态-假基因-生殖隔离-性选择。
We used mitochondrial [cytochrome c oxidase subunit I (CO I), cytochrome b, and 16S] and nuclear [internal transcribed spacer (ITS) phylogenies of Skistodiaptomus copepods to test hypotheses of Pleistocene divergence and speciation within the genus. Mitochondrial (mt)DNA sequence divergences do not support hypotheses for Pleistocene speciation and instead suggest much more ancient speciation events in the genus. Skistodiaptomus oregonensis and Skistodiaptomus pygmaeus (i.e. two morphologically similar and parapatric species) exhibited uncorrected mtDNA sequence divergences exceeding 20%. Similarly, we identified three divergent clades of Skistodiaptomus pallidus that exhibited mtDNA sequence divergences exceeding 15%, suggesting that even intraspecific divergence within this morphospecies predates the Pleistocene. We found clear evidence of CO I pseudogenes in S. pygmaeus, but their presence did not lead to significant overestimates of sequence divergences for this gene. Substitution saturation and strong purifying selection have most likely led to underestimates of sequence divergences and divergence times among Skistodiaptomus. The widespread phenomenon of morphological stasis among genetically divergent copepod groups indicates that speciation often occurs with little or no morphological change. Instead, morphological evolution may occur idiosyncratically after speciation and create discordant patterns of morphological similarity, shared ancestry and divergence time. Cryptic species complexes are therefore common in copepods, and morphological species concepts underestimate their true species diversity. © 2009 The Linnean Society of London, Biological Journal of the Linnean Society, 2009, 96, 150‐165. ADDITIONAL KEYWORDS: cryptic species ‐ genitalia ‐ intrinsic incompatibility ‐ molecular clocks ‐ molecular phylogeny ‐ morphological stasis ‐ Pleistoscenario ‐ pseudogenes ‐ reproductive isolation ‐ sexual selection.
影响因子：
3.3
作者：
Lee, CE
通讯作者：
Lee, CE