Invasion genetics of the Ciona intestinalis species complex: from regional endemism to global homogeneity
Invasion genetics of the Ciona intestinalis species complex: from regional endemism to global homogeneity
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DOI：
10.1111/j.1365-294x.2010.04837.x
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发表时间：
2010-11
影响因子：
4.9
通讯作者：
Aibin Zhan;H. MacIsaac;M. Cristescu
中科院分区：
文献类型：
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作者：
Aibin Zhan;H. MacIsaac;M. Cristescu
确定种群的连接程度和调查在不同地理尺度上驱动遗传交换的因素对于理解种群动态和入侵物种的传播潜力至关重要。在这里，我们探讨了这些问题，在高度侵入性的花瓶被囊，玻璃海鞘，一个物种的入侵历史已被其知之甚少的分类学和种群遗传学模糊。最近的系统发育和比较基因组研究表明，C。隐翅虫是一个由至少三个物种组成的隐种复合体。基于线粒体（细胞色素c氧化酶亚基3-NADH脱氢酶亚基1区和NADH脱氢酶亚基4基因）和核（内转录间隔区1）序列，我们重建了它们的同源性，结果支持了4个主要的同源性类群，分别对应于先前报道的spA、spB和玻璃海鞘。(spC)以及一种未描述的神秘物种（spD）。虽然spC和spD仍然分别局限于它们在地中海和黑海的原生范围，但高度入侵的物种（spA和spB）具有间断的全球分布。尽管广泛的种间分歧，我们确定了低海拔的地理结构，这两个入侵物种。单倍型网络分析显示，每个物种内的单倍型之间的突变步骤相对有限。基于两个mtDNA片段和8个非连锁微卫星的种群遗传分析表明，在区域和大陆尺度上，两种入侵物种的种群分化相对较低，种群连接性较高。人类介导的传播加上自然传播的高潜力可能是观察到的遗传同质性的原因。
Determining the degree of population connectivity and investigating factors driving genetic exchange at various geographical scales are essential to understanding population dynamics and spread potential of invasive species. Here, we explore these issues in the highly invasive vase tunicate, Ciona intestinalis, a species whose invasion history has been obscured by its poorly understood taxonomy and population genetics. Recent phylogenetic and comparative genomic studies suggest that C. intestinalis is a cryptic species complex consisting of at least three species. We reconstructed phylogenies based on both mitochondrial (cytochrome c oxidase subunit 3—NADH dehydrogenase subunit 1 region and NADH dehydrogenase subunit 4 gene) and nuclear (internal transcribed spacer 1) sequences, results of which support four major phylogroups corresponding to the previously reported spA, spB and Ciona spp. (spC) as well as an undescribed cryptic species (spD). While spC and spD remain restricted to their native ranges in the Mediterranean Sea and Black Sea, respectively, the highly invasive species (spA and spB) have disjunct global distributions. Despite extensive interspecific divergences, we identified low phylogeographical structure within these two invasive species. Haplotype network analyses revealed comparatively limited mutation steps among haplotypes within each species. Population genetic analyses based on two mtDNA fragments and eight unlinked microsatellites illustrated relatively low population differentiation and high population connectivity at both regional and continental scales in the two invasive species. Human‐mediated dispersal coupled with a high potential for natural dispersal is probably responsible for the observed genetic homogeneity.