Bastrop R, Strehlow B, Jürss K, Sturmbauer C
Institute of Biodiversity Research, University of Rostock, Justus-von-Liebig-Weg 8, Rostock, D-18051, Germany.
Mol Phylogenet Evol. 2000 Feb;14(2):250-8. doi: 10.1006/mpev.1999.0694.
Phylogenetic analysis of a segment of the mitochondrial 16S rDNA of eight Anguilla species from the Indo-Pacific region and from the North Atlantic revealed that the genus Anguilla appears to be surprisingly young, based upon the small observed maximum genetic distance of 4.8% and the high degree of morphological similarity among the species. The placement of A. marmorata as the most ancestral lineage suggests that the genus is likely to have originated in the Indo-Malayian region, from which it quickly spread. Two Pacific species, A. obscura and A. japonica, branched next. A. japonica was placed as sister group to all remaining species, which formed three clades: the first comprising A. australis, the second A. reinhardti and A. mossambica, and the third A. anguilla and A. rostrata. All analyzed specimens of A. rostrata originating from southern New Jersey to Nova Scotia had identical mitotypes, while five mitochondrial genotypes were found in Europe differing by zero to two substitutions. The two Atlantic eel species are very closely related; all surveyed specimens of A. anguilla differ by three to five substitutions from their American allies, corroborating the existence of two distinct biological species. This was also confirmed by restriction analysis of a 350-bp segment of the cytochrome b, in which American specimens were distinct in sharing a single diagnostic restriction site of HinfI. Our results suggest little to no gene flow between the two nominal Atlantic eel species.
对来自印度-太平洋地区和北大西洋的8种鳗鲡属物种的线粒体16S rDNA片段进行系统发育分析后发现，基于观察到的仅4.8%的最小遗传距离以及各物种间高度的形态相似性，鳗鲡属似乎出奇地年轻。斑纹鳗鲡作为最原始的谱系表明该属可能起源于印度-马来西亚地区，并从那里迅速扩散。接下来分支的是两种太平洋物种，即暗色鳗鲡和日本鳗鲡。日本鳗鲡被置于所有其余物种的姐妹群位置，其余物种形成三个进化枝：第一个进化枝包括澳大利亚鳗鲡，第二个包括雷氏鳗鲡和莫桑比克鳗鲡，第三个包括欧洲鳗鲡和美洲鳗鲡。所有来自新泽西州南部到新斯科舍省的美洲鳗鲡分析样本都具有相同的线粒体类型，而在欧洲发现了五种线粒体基因型，差异为零至两个碱基替换。这两种大西洋鳗鱼物种关系非常密切；所有调查的欧洲鳗鲡样本与其美洲同类的差异为三至五个碱基替换，证实了存在两个不同的生物物种。这也通过对细胞色素b的350 bp片段的限制性分析得到证实，其中美洲样本在共享单个HinfI诊断限制性位点方面是独特的。我们的结果表明，这两种名义上的大西洋鳗鱼物种之间几乎没有基因流动。
