Xu Ting, Sun Jin, Watanabe Hiromi K, Chen Chong, Nakamura Masako, Ji Rubao, Feng Dong, Lv Jia, Wang Shi, Bao Zhenmin, Qian Pei-Yuan, Qiu Jian-Wen
Department of Biology Hong Kong Baptist University Hong Kong China.
Department of Ocean Science Hong Kong University of Science and Technology Hong Kong China.
Evol Appl. 2018 Oct 12;11(10):1915-1930. doi: 10.1111/eva.12696. eCollection 2018 Dec.
Studying population genetics of deep-sea animals helps us understand their history of habitat colonization and population divergence. Here, we report a population genetic study of the deep-sea mussel (Bivalvia: Mytilidae) widely distributed in chemosynthesis-based ecosystems in the Northwest Pacific. Three mitochondrial genes (i.e., , , and ) and 6,398 genomewide single nucleotide polymorphisms (SNPs) were obtained from 110 individuals from four hydrothermal vents and two methane seeps. When using the three mitochondrial genes, nearly no genetic differentiation was detected for in the Northwest Pacific. Nevertheless, when using SNP datasets, all individuals in the South China Sea (SCS) and three individuals in Sagami Bay (SB) together formed one genetic cluster that was distinct from the remaining individuals. Such genetic divergence indicated a genetic barrier to gene flow between the SCS and the open Northwest Pacific, resulting in the co-occurrence of two cryptic semi-isolated lineages. When using 125 outlier SNPs identified focusing on individuals in the Okinawa Trough (OT) and SB, a minor genetic subdivision was detected between individuals in the southern OT (S-OT) and those in the middle OT (M-OT) and SB. This result indicated that, although under the influence of the Kuroshio Current and the North Pacific Intermediate Water, subtle geographic barriers may exist between the S-OT and the M-OT. Introgression analyses based on these outlier SNPs revealed that Hatoma Knoll in the S-OT represents a possible contact zone for individuals in the OT-SB region. Furthermore, migration dynamic analyses uncovered stronger gene flow from Dai-yon Yonaguni Knoll in the S-OT to the other local populations, compared to the reverse directions. Taken together, the present study offered novel perspectives on the genetic connectivity of mussels, revealing the potential interaction of ocean currents and geographic barriers with adaption and reproductive isolation in shaping their migration patterns and genetic differentiation in the Northwest Pacific.
研究深海动物的种群遗传学有助于我们了解它们的栖息地殖民历史和种群分化情况。在此，我们报告了一项对广泛分布于西北太平洋基于化学合成的生态系统中的深海贻贝（双壳纲：贻贝科）的种群遗传学研究。从四个热液喷口和两个甲烷冷泉的110个个体中获得了三个线粒体基因（即 、 和 ）以及6398个全基因组单核苷酸多态性（SNP）。使用这三个线粒体基因时，在西北太平洋几乎未检测到 的遗传分化。然而，使用SNP数据集时，南海（SCS）的所有个体和相模湾（SB）的三个个体共同形成了一个与其余个体不同的遗传簇。这种遗传分化表明南海与开阔的西北太平洋之间存在基因流动的遗传障碍，导致两个隐秘的半隔离谱系共存。使用针对冲绳海槽（OT）和SB个体鉴定出的125个异常SNP时，在南冲绳海槽（S - OT）个体与中冲绳海槽（M - OT）和SB个体之间检测到了轻微的遗传细分。这一结果表明，尽管受到黑潮和北太平洋中层水的影响，但S - OT和M - OT之间可能存在微妙的地理障碍。基于这些异常SNP的渐渗分析表明，S - OT的波照间海丘代表了OT - SB区域个体的一个可能接触区。此外，迁移动态分析发现，与相反方向相比，S - OT的大宜野湾海丘向其他当地种群的基因流动更强。综上所述，本研究为贻贝的遗传连通性提供了新的视角，揭示了洋流和地理障碍在塑造西北太平洋贻贝迁移模式和遗传分化过程中与适应和生殖隔离的潜在相互作用。
