Data from: Connectivity in the cold: the comparative population genetics of vent-endemic fauna in the Scotia Sea, Southern Ocean.

We report the first comparative population genetics study for vent fauna in the Southern Ocean using cytochrome C oxidase I and microsatellite markers. Three species are examined: the kiwaid squat lobster, Kiwa tyleri, the peltospirid gastropod Gigantopelta chessoia and a lepetodrilid limpet, Lepetodrilus sp. collected from vent fields 440 km apart on the East Scotia Ridge (ESR) and from the Kemp Caldera on the South Sandwich Island Arc, ~95 km eastwards. We report no differentiation for all species across the ESR, consistent with panmixia or recent range expansions. A lack of differentiation is notable for Kiwa tyleri, which exhibits extremely abbreviated lecithotrophic larval development, suggestive of a very limited dispersal range. Larval lifespans may, however, be extended by low temperature-induced metabolic rate reduction in the Southern Ocean, muting the impact of dispersal strategy on patterns of population structure. COI diversity patterns suggest all species experienced demographic bottlenecks or selective sweeps in the past million years and possibly at different times. ESR and Kemp limpets are divergent, although with evidence of very recent ESR-Kemp immigration. Their divergence, possibility indicative of incipient speciation, along with the absence of the other two species at Kemp, may be the consequence of differing dispersal capabilities across a ~1000 m depth range and/or different selective regimes between the two areas. Estimates of historic and recent limpet gene flow between the ESR and Kemp are consistent with predominantly easterly currents in the region and potentially therefore, cross-axis currents on the ESR, with biogeographic implications for the region.

本研究首次利用细胞色素C氧化酶亚基I（cytochrome C oxidase I, COI）与微卫星标记（microsatellite markers），对南大洋热液喷口动物群开展比较种群遗传学研究。本次研究选取三个物种进行分析：采自斯科舍海岭（East Scotia Ridge, ESR）上相距440公里的热液喷口区，以及南桑威奇群岛弧东侧约95公里处的肯普破火山口（Kemp Caldera）的基瓦类铠甲虾——泰勒基瓦铠虾（Kiwa tyleri）、皮螺科腹足类——切氏巨皮螺（Gigantopelta chessoia），以及鳞帽贝科帽贝未定种（Lepetodrilus sp.）。
研究结果显示，斯科舍海岭区域内所有物种均未出现种群分化，这与泛交（panmixia）或近期种群范围扩张的结论相符。其中泰勒基瓦铠虾的种群无分化现象尤为值得关注：该物种具有极度简化的卵黄营养型幼虫发育模式，理论上其扩散范围应极为有限。但南大洋的低温环境可通过降低代谢速率延长幼虫寿命，从而削弱扩散策略对种群结构的影响。
COI序列的多样性模式表明，所有物种在过去百万年间均经历过种群瓶颈或选择性清除事件，且发生时间可能各不相同。
斯科舍海岭与肯普破火山口的鳞帽贝种群存在遗传分化，但存在近期斯科舍海岭向肯普破火山口迁入的分子证据。二者的分化可能代表初期物种形成，结合另外两个物种未在肯普破火山口出现的现象，这或许是1000米左右深度梯度下扩散能力差异，以及两处区域选择压力环境不同共同导致的结果。
对斯科舍海岭与肯普破火山口之间鳞帽贝的历史和近期基因流的估算结果，与该区域以东风流为主的洋流模式相符，同时也暗示斯科舍海岭存在轴跨洋流，这对该区域的生物地理学研究具有重要意义。