Vendrami David L J, Peck Lloyd S, Clark Melody S, Eldon Bjarki, Meredith Michael, Hoffman Joseph I
Department of Animal Behaviour, Bielefeld University, Postfach 100131, 33501 Bielefeld, Germany.
British Antarctic Survey, High Cross, Madingley Road, Cambridge CB3 OET, UK.
Sci Adv. 2021 Sep 10;7(37):eabj4713. doi: 10.1126/sciadv.abj4713.
A long-standing paradox of marine populations is chaotic genetic patchiness (CGP), temporally unstable patterns of genetic differentiation that occur below the geographic scale of effective dispersal. Several mechanisms are hypothesized to explain CGP including natural selection, spatiotemporal fluctuations in larval source populations, self-recruitment, and sweepstake reproduction. Discriminating among them is extremely difficult but is fundamental to understanding how marine organisms reproduce and disperse. Here, we report a notable example of CGP in the Antarctic limpet, an unusually tractable system where multiple confounding explanations can be discounted. Using population genomics, temporally replicated sampling, surface drifters, and forward genetic simulations, we show that CGP likely arises from an extreme sweepstake event together with collective larval dispersal, while selection appears to be unimportant. Our results illustrate the importance of neutral demographic forces in natural populations and have important implications for understanding the recruitment dynamics, population connectivity, local adaptation, and resilience of marine populations.
海洋种群长期存在的一个悖论是混沌遗传斑块性（CGP），即在有效扩散的地理尺度以下出现的遗传分化的时间不稳定模式。人们假设了几种机制来解释CGP，包括自然选择、幼虫源种群的时空波动、自我补充和抽奖式繁殖。区分这些机制极其困难，但对于理解海洋生物如何繁殖和扩散至关重要。在这里，我们报告了南极帽贝中一个显著的CGP例子，这是一个异常易于处理的系统，其中多种混杂的解释可以被排除。通过群体基因组学、时间上重复采样、表面漂流器和正向遗传模拟，我们表明CGP可能源于极端的抽奖事件以及幼虫的集体扩散，而选择似乎并不重要。我们的结果说明了中性种群统计学力量在自然种群中的重要性，并对理解海洋种群的补充动态、种群连通性、局部适应性和恢复力具有重要意义。
