Sogabe Atsushi, Takagi Motohiro
Graduate School of Biosphere Science, Hiroshima University, 1-4-4 Kagamiyama, Higashi-Hiroshima, 739-8528 Japan ; Center for Marine Biology, Asamushi, Tohoku University, 9 Sakamoto Asamushi, Aomori, 039-3501 Japan.
Springerplus. 2013 Aug 28;2:408. doi: 10.1186/2193-1801-2-408. eCollection 2013.
The population genetic structure of the messmate pipefish, Corythoichthys haematopterus, in the northwest Pacific was investigated based on the partial mitochondrial DNA cytochrome b (589 bp) and 16S rRNA (528 bp) region sequences of 108 individuals collected from six sites along the coast of the Japanese archipelago and one site on Mactan Island, the Philippines. A total of 60 and 28 haplotypes were obtained from the cytochrome b and 16S rRNA regions, respectively. Two genetically distinct lineages were detected: lineage A and B, which are separated by mean pairwise genetic distances of 23.3 and 14.1% in the partial cytochrome b and 16S rRNA genes, respectively. Such a huge genetic divergence between lineages, which is comparable to or even higher than the interspecific level, and the difference in their geographical distributions and habitat preferences suggests that they are distinct species, although there is no marked difference in their morphology. Haplotype network and gene and nucleotide diversity statistics indicate that the two lineages have different biogeographic histories: lineage A experienced rapid population expansion after a population bottleneck whereas lineage B has a long evolutionary history in a large stable population. In contrast, the levels of genetic variation among populations are relatively low in both lineages, probably because of frequent gene flow among populations resulting from the dispersal of pelagic larvae by the Kuroshio Current. These results indicate that past climatic events and contemporary oceanographic features have played a major role in establishing the population genetic structure of C. haematopterus.
基于从日本列岛沿岸六个地点以及菲律宾马克坦岛一个地点采集的108个个体的线粒体DNA细胞色素b（589 bp）和16S rRNA（528 bp）区域部分序列，对西北太平洋的红鳍冠海龙（Corythoichthys haematopterus）的种群遗传结构进行了研究。分别从细胞色素b和16S rRNA区域获得了60个和28个单倍型。检测到两个遗传上不同的谱系：谱系A和谱系B，它们在细胞色素b和16S rRNA基因部分的平均成对遗传距离分别为23.3%和14.1%。谱系之间如此巨大的遗传差异，与种间水平相当甚至更高，以及它们在地理分布和栖息地偏好上的差异表明，尽管它们在形态上没有明显差异，但它们是不同的物种。单倍型网络以及基因和核苷酸多样性统计表明，这两个谱系具有不同的生物地理历史：谱系A在经历种群瓶颈后经历了快速的种群扩张，而谱系B在一个大型稳定种群中具有悠久的进化历史。相反，两个谱系中种群间的遗传变异水平相对较低，这可能是由于黑潮导致的浮游幼体扩散使种群间频繁发生基因流动。这些结果表明，过去的气候事件和当代海洋学特征在红鳍冠海龙种群遗传结构的形成中起了主要作用。
