Dispersal barriers in tropical oceans and speciation in Atlantic and eastern Pacific sea urchins of the genus Echinometra
Dispersal barriers in tropical oceans and speciation in Atlantic and eastern Pacific sea urchins of the genus Echinometra
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DOI：
10.1046/j.1365-294x.2000.01022.x
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发表时间：
2000-09-01
影响因子：
4.9
通讯作者：
Lessios, HA
中科院分区：
文献类型：
--
作者：
McCartney, MA;Keller, G;Lessios, HA
棘皮海胆是一种泛热带海胆，通过对印度-西太平洋(IWP)物种的系统发育、物种形成和遗传结构的研究而闻名。我们对细胞色素氧化酶I(COI)线粒体基因进行了630个碱基的测序，以提供东太平洋和大西洋物种的可比信息，并利用310万年前巴拿马地峡关闭(Ma)分隔的物种之间的分歧来估计分支形成事件的日期。最近(1.27-1.62 Ma)，大西洋物种E.Lucunter和E.viridis在更新世海平面下降，加勒比海珊瑚物种形成和灭绝率很高的时候彼此背离。早些时候的一次分裂，被认为是与巴拿马地峡的完成重合，将东太平洋的E.Vanbrunti与大西洋的共同祖先分开。与海胆属Eucidaris类似的Transsthmian COI发散支持这一假设。Echinmetra最古老的分裂发生在IWP和新热带分支之间，原因是南非周围或跨越东太平洋屏障的幼虫交流停止。目前，物种内的基因普遍很高；然而，来自加勒比海和大西洋其他地区的卢肯特棘豆种群之间的遗传交流受到限制。分支起源事件和替代事件之间的相关性支持E.Mayr的观点，即尽管海洋物种具有很高的扩散潜力，但它们是通过地理分离的方式形成的。然而，共域的、非杂交的Lucunter和E.viridis最近分裂表明，拥有大量种群的海洋物种之间的生殖障碍可能在不到160万年(Myr)内完成。
Echinometra is a pantropical sea urchin made famous through studies of phylogeny, speciation, and genetic structure of the Indo-West Pacific (IWP) species. We sequenced 630 bp of the cytochrome oxidase I (COI) mitochondrial gene to provide comparable information on the eastern Pacific and Atlantic species, using divergence between those separated by closure of the Isthmus of Panama 3.1 million years ago (Ma) to estimate dates for cladogenic events. Most recently (1.27-1.62 Ma), the Atlantic species E. lucunter and E. viridis diverged from each other at a time in the Pleistocene that sea levels fell and Caribbean coral speciation and extinction rates were high. An earlier split, assumed to have been coincident with the completion of the Isthmus of Panama, separated the eastern Pacific E. vanbrunti from the Atlantic common ancestor. Transisthmian COI divergence similar to that in the sea urchin genus Eucidaris supports this assumption. The most ancient split in Echinometra occurred between the IWP and the neotropical clades, due to cessation of larval exchange around South Africa or across the Eastern Pacific Barrier. Gene now within species is generally high; however there are restrictions to genetic exchange between E. lucunter populations from the Caribbean and those from the rest of the Atlantic. Correlation between cladogenic and vicariant events supports E. Mayr's contention that marine species, despite their high dispersal potential, form by means of geographical separation. That sympatric, nonhybridizing E. lucunter and E. viridis were split so recently suggests, however, that perfection of reproductive barriers between marine species with large populations can occur in less than 1.6 million years (Myr).