Extreme population genetic differentiation and secondary contact in the freshwater copepod Acanthodiaptomus pacificus in the Japanese Archipelago
Extreme population genetic differentiation and secondary contact in the freshwater copepod Acanthodiaptomus pacificus in the Japanese Archipelago
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DOI：
10.1111/j.1365-294x.2009.04307.x
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发表时间：
2009-09-01
影响因子：
4.9
通讯作者：
Tanabe, Akifumi S.
中科院分区：
文献类型：
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作者：
Makino, Wataru;Tanabe, Akifumi S.
我们调查了日本哲水蚤桡足类太平洋镖水蚤线粒体细胞色素c氧化酶亚基1（mtCOI）基因和核核糖体内转录间隔区（ncITS）的序列变异。A.太平洋牡蛎个体分为三个不同的mtCOI谱系（mt-A、-B和-C）。mt-A分布于日本最北部，从北海道到本州岛北方; mt-C分布于日本最南部，从本州岛中部到四国和九州岛。mt-B分布在前两个谱系之间，导致与mt-C和mt-A的平行关系。在所有谱系中，80%的地点是固定的单一单倍型，不同的地点往往有不同的单倍型。根据DNA条形码技术的标准，这些谱系之间的遗传分化程度（15-22%）处于种间水平。然而，ncITS的拓扑结构与mtCOI的拓扑结构并不一致，因为在mt-B和mt-C中没有观察到相互的单系性。因此，我们将它们合并到南方血统中，并将其与北方血统（即mt-A）分开。在南方系中发现了基因渐渗的证据，而在北方和南方系之间没有观察到基因流动，这表明A. pacificus是一个神秘的物种复合体。我们还认为，A. pacificus可能反映了现今日本列岛形成过程中陆块分离、海侵和海退的历史。
We investigated the sequence variation in the mitochondrial cytochrome c oxidase subunit 1 (mtCOI) gene and the nuclear ribosomal internal transcribed spacers (ncITS) of the calanoid copepod Acanthodiaptomus pacificus in Japan. A. pacificus individuals were divided into three divergent mtCOI lineages (mt-A, -B and -C). mt-A was distributed in the northernmost part of Japan, from Hokkaido to the northern part of Honshu Island, whereas mt-C was the southernmost lineage, distributed from central Honshu to Shikoku and Kyushu Islands. mt-B was distributed between these former two lineages, resulting in parapatry with mt-C and mt-A. In all lineages, 80% of the localities were fixed for a single haplotype, and different localities tended to have different haplotypes. The degree of genetic differentiation among these lineages (15-22%) was at an interspecific level, according to the criteria of the DNA barcode technique. However, the topology of ncITS was not congruent with that of mtCOI, as the reciprocal monophyly was not observed within mt-B and mt-C. Therefore, we merged them into the Southern Lineage and separated it from the Northern Lineage (i.e. mt-A). Evidence of introgression was found within the Southern Lineage, while gene flow was not observed between the Northern and Southern Lineages, suggesting that A. pacificus is a cryptic species complex. We also argue that genetic differentiations of A. pacificus in Japan may reflect the history of separation, transgression and regression of the landmass during the formation of current Japanese Archipelago.