UWA Oceans Institute & School of Plant Biology, The University of Western Australia, Crawley, 6009, WA, Australia.
Australian Institute of Marine Science, Crawley, 6009, WA, Australia.
Sci Rep. 2017 Aug 17;7(1):8618. doi: 10.1038/s41598-017-09224-y.
Understanding source-sink dynamics is important for conservation management, particularly when climatic events alter species' distributions. Following a 2011 'marine heatwave' in Western Australia, we observed high recruitment of the endemic fisheries target species Choerodon rubescens, towards the cooler (southern) end of its distribution. Here, we use a genome wide set of 14 559 single-nucleotide polymorphisms (SNPs) to identify the likely source population for this recruitment event. Most loci (76%) showed low genetic divergence across the species' range, indicating high levels of gene flow and confirming previous findings using neutral microsatellite markers. However, a small proportion of loci showed strong patterns of differentiation and exhibited patterns of population structure consistent with local adaptation. Clustering analyses based on these outlier loci indicated that recruits at the southern end of C. rubescens' range originated 400 km to the north, at the centre of the species' range, where average temperatures are up to 3 °C warmer. Survival of these recruits may be low because they carry alleles adapted to an environment different to the one they now reside in, but their survival is key to establishing locally adapted populations at and beyond the range edge as water temperatures increase with climate change.
了解源汇动态对于保护管理很重要，特别是在气候事件改变物种分布时。在 2011 年西澳大利亚的一次“海洋热浪”之后，我们观察到本地渔业目标物种红拟石首鱼（Choerodon rubescens）在其分布范围的较冷（南部）端高度繁殖。在这里，我们使用一组 14559 个单核苷酸多态性（SNP）的全基因组来确定这次繁殖事件的可能来源种群。大多数（76%）基因座在物种分布范围内显示出低遗传分化，表明存在高水平的基因流，并证实了以前使用中性微卫星标记的研究结果。然而，一小部分基因座显示出强烈的分化模式，并表现出与局部适应一致的种群结构模式。基于这些异常基因座的聚类分析表明，在 C. rubescens 分布范围南端的繁殖体起源于北部 400 公里处，即物种分布范围的中心，那里的平均温度高出 3°C。这些繁殖体的存活率可能较低，因为它们携带适应于与它们现在所处环境不同的环境的等位基因，但它们的存活对于在水温随气候变化升高时在范围边缘建立和超越本地适应种群至关重要。
