The phylogeography of dusky dolphins (Lagenorhynchus obscurus):: a critical examination of network methods and rooting procedures
The phylogeography of dusky dolphins (Lagenorhynchus obscurus):: a critical examination of network methods and rooting procedures
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DOI：
10.1046/j.1365-294x.2003.01876.x
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发表时间：
2003-07-01
影响因子：
4.9
通讯作者：
Milinkovitch, MC
中科院分区：
文献类型：
--
作者：
Cassens, I;Van Waerebeek, K;Milinkovitch, MC
我们使用来自秘鲁、阿根廷和西南非洲假定种群的 124 只暗色海豚 (Lagenorhynchus obscurus) 的完整线粒体细胞色素 b 基因的 DNA 序列，研究了暗色海豚 (Lagenorhynchus obscurus) 的系统发育地理学和进化史。虽然海洋内的遗传分化出人意料地低，但没有证据表明最近大西洋和太平洋水域之间存在雌性基因流动。就序列差异和单倍型数量而言，遗传变异性最高的是大西洋。我们的分析还表明，南太平洋东部暗色海豚种群应被视为一个单独的管理单位。鉴于秘鲁暗色斑纹海豚在当地渔业活动中的死亡率很高，这些发现对该物种的客观管理具有重要意义。此外，我们使用几种广泛使用的网络估计和生根方法分析了线粒体序列数据。由此产生的种内基因谱系和根源推论表现出巨大的差异，这是某些算法的局限性的基础。鉴于科学假设和管理决策在很大程度上依赖于推断的树或网络拓扑，因此显然需要对可用方法进行系统的比较分析。最后，本研究表明（i）暗色海豚和太平洋白海豚是姐妹物种，（ii）不仅西风漂流假说而且其他分散模型都与暗色海豚当前的地理分布相一致。
We investigated the phylogeography and evolutionary history of dusky dolphins (Lagenorhynchus obscurus ) using DNA sequences of the full mitochondrial cytochrome b gene in 124 individuals from the putative stocks off Peru, Argentina and Southwest Africa. While genetic differentiation within oceans is surprisingly low, there is no evidence for recent female gene flow between Atlantic and Pacific waters. Highest genetic variability in terms of sequence divergence and number of haplotypes is found in the Atlantic. Our analyses also indicate that the eastern South Pacific dusky dolphins stock should be considered a separate management unit. Given the high level of mortality experienced by the Peruvian dusky dolphin in local fishery activities, these findings have important implications for an objective management of the species. Furthermore, we analysed our mitochondrial sequence data with several widely used network estimation and rooting methods. The resulting intraspecific gene genealogies and rooting inferences exhibited substantial differences, underlying the limitations of some algorithms. Given that scientific hypotheses and management decisions depend strongly on inferred tree or network topologies, there is a clear need for a systematic comparative analysis of available methods. Finally, the present study indicates that (i) the dusky and the Pacific white-sided dolphins are sister species and (ii) not only the Westwind Drift hypothesis but also other models of dispersion are compatible with the current geographical distribution of dusky dolphins.