Phylogeny and biogeography of Hydra (Cnidaria: Hydridae) using mitochondrial and nuclear DNA sequences
Phylogeny and biogeography of Hydra (Cnidaria: Hydridae) using mitochondrial and nuclear DNA sequences
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DOI：
10.1016/j.ympev.2010.06.016
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发表时间：
2010-10-01
影响因子：
4.1
通讯作者：
Campbell, R. D.
中科院分区：
文献类型：
--
作者：
Martinez, D. E.;Iniguez, A. R.;Campbell, R. D.
水螅在淡水中普遍存在，并且高度可变，有许多种名称分配给不同的菌株。水螅的类型确实可以分为四个形态上可识别的组，但许多物种的确定是混乱的。为了评估水螅的多样性，我们收集了来自六大洲的101株水螅，并使用三个遗传标记建立了一个系统发育。这四个明确定义的物种群中的每一个都代表了我们进化史中的一个分支。首先是绿色水螅群，其次是braueri群，最后是姐妹群vulgaris和oligactis。八个物种中的每一个都很容易通过形态学标准来定义，代表了我们的进化史中的一个独特的分支。水螅有两个分支，绿色水螅和普通水螅，在所有大陆（南极洲除外）和许多岛屿上都有发现，而其他两个群体（braueri和oligactis）的水螅仅限于北方半球。我们对水螅起源时间的最佳估计是大约60 Ma，在盘古大陆断裂成北方和南方陆块之后很久。九头蛇似乎在北方半球已经多样化了，它们目前的多样性在这里最大。两个物种能够分散到南半球，可能是由于它们的耐热性。(C)2010年爱思唯尔公司All rights reserved.
The polyp hydra is ubiquitous in freshwater and is highly variable, with many species names assigned to different strains. Types of hydra do fall into four morphologically recognizable groups but many of the species determinations are confusing. To assess the diversity of hydra we collected 101 strains from six continents and built a phylogeny using three genetic markers. Each of the four well-defined groups of species represents a clade in our phylogeny. The green hydra group diverged first, followed by the braueri group and finally the sister groups vulgaris and oligactis. Each of eight species easily definable by morphological criteria represents a distinct clade in our phylogeny. Hydra of two clades, the green and the vulgaris hydra, are found on all continents (except Antarctica) and many islands, whereas hydra of the other two groups (braueri and oligactis) are restricted to the Northern Hemisphere. Our best estimate of the time of origin of hydra is about 60 Ma, long after the breakage of Pangea into northern and southern landmasses. Hydra appear to have diversified in the Northern Hemisphere, and their current diversity is greatest here. Two species were then able to disperse to the Southern Hemisphere, perhaps due to their thermal tolerance. (C) 2010 Elsevier Inc. All rights reserved.