During the Last Glacial Maximum (LGM), global sea levels were 120–130 m lower than today, resulting in the emergence of most continental shelves and extirpation of subtidal organisms from these areas. During the interglacial periods, rapid inundation of shelf regions created a dynamic environment for coastal organisms, such as the charismatic leafy seadragon (Phycodurus eques, Syngnathidae), a brooder with low dispersal ability inhabiting kelp beds in temperate Australia. Reconstructions of the palaeoshoreline revealed that the increase of shallow areas since the LGM was not uniform across the species' range and we investigated the effects of these asymmetries on genetic diversity and structuring. Using targeted capture of 857 variable ultraconserved elements (UCEs, 2,845 single nucleotide polymorphisms) in 68 individuals, we found that the regionally different shelf topographies were paralleled by contrasting population genetic patterns. In the west, populations may not have persisted through sea‐level lows because shallow seabed was very limited. Shallow genetic structure, weak expansion signals and a westward cline in genetic diversity indicate a postglacial recolonization of the western part of the range from a more eastern location following sea‐level rise. In the east, shallow seabed persisted during the LGM and increased considerably after the flooding of large bays, which resulted in strong demographic expansions, deeper genetic structure and higher genetic diversity. This study suggests that postglacial flooding with rising sea levels produced locally variable signatures in colonizing populations.

中文翻译：

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利用超保守元素追踪海平面变化对叶海龙种群的影响


在末次盛冰期 (LGM)，全球海平面比现在低 120-130 m，导致大多数大陆架出现，潮下生物从这些地区灭绝。在间冰期，陆架区域的快速淹没为沿海生物创造了一个充满活力的环境，例如魅力十足的叶海龙（ Phycodurus eques ，Syngnathidae），这是一种栖息在澳大利亚温带海藻床上的低扩散能力的育雏者。古海岸线的重建表明，末次盛冰期以来浅水区域的增加在整个物种范围内并不均匀，我们研究了这些不对称性对遗传多样性和结构的影响。通过对 68 个个体的 857 个可变超保守元件（UCE，2,845 个单核苷酸多态性）进行定向捕获，我们发现区域不同的架子地形通过对比的群体遗传模式而平行。在西方，由于浅海床非常有限，人口可能无法在海平面低点持续存在。浅的遗传结构、微弱的扩张信号和遗传多样性的向西倾斜表明，随着海平面上升，冰期后该地区从更东部的位置开始重新殖民。在东部，末次盛冰期期间，浅海床持续存在，并在大海湾洪水泛滥后大幅增加，导致人口强劲扩张、遗传结构更深、遗传多样性更高。这项研究表明，随着海平面上升，冰河后洪水在殖民群体中产生了局部变化的特征。