Reef-building corals are foundational species in coral reef ecosystems and are threatened by many stressors including rising ocean temperatures. In 2015/16 and 2016/17, corals around the world experienced consecutive bleaching events and most coral populations are projected to experience temperatures above their current bleaching thresholds annually by 2050. Adaptation to higher temperatures is therefore necessary if corals are to persist in a warming future. While many aspects of heat stress have been well studied, few data are available for predicting the capacity for adaptive cross-generational responses in corals. To address this knowledge gap, we quantified the heritability and genetic variation associated with heat tolerance in Platygyra daedalea from the Great Barrier Reef (GBR). We tracked the survival of replicate quantitative genetic crosses (or families) of coral larvae from six parents in a heat stress selection experiment. We also identified allelic shifts in heat-selected survivors versus paired, non-selected controls of the same coral crosses. We estimated narrow sense heritability to be 0.66 and detected a total of 1,069 single nucleotide polymorphisms (SNPs) associated with heat tolerance. An overlap of 148 unique SNPs shared between experimental crosses indicates that specific genomic regions are responsible for heat tolerance of P. daedalea and some of these SNPs fall in coding regions. These findings suggest that this P. daedalea population has the genetic prerequisites for adaptation to increasing temperatures. This study also provides knowledge for the development of high throughput genomic tools to screen for variation within and across populations to harness or enhance adaptation through assisted gene flow and assisted migration.

中文翻译：

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珊瑚桔梗的耐热性遗传变异为适应海洋变暖提供了潜力

造礁珊瑚是珊瑚礁生态系统中的基础物种，受到包括海洋温度升高在内的许多压力的威胁。在2015/16和2016/17年，世界各地的珊瑚经历了连续的漂白事件，预计到2050年，每年大多数珊瑚种群的温度将超过其当前的漂白阈值。因此，如果珊瑚要持续变暖，就必须适应更高的温度。未来。尽管已经对热应激的许多方面进行了深入研究，但很少有数据可用于预测珊瑚适应跨代反应的能力。为了解决这一知识鸿沟，我们量化了与桔梗耐热性相关的遗传力和遗传变异。来自大堡礁（GBR）。在热应激选择实验中，我们追踪了来自六个亲本的珊瑚幼虫重复定量遗传杂交（或科）的存活情况。我们还确定了热选择幸存者与配对，非选择的同一珊瑚杂交对照的等位基因转移。我们估计窄义遗传力为0.66，并检测到总共1,069个与耐热性相关的单核苷酸多态性（SNP）。实验杂交之间共享的148个独特SNP的重叠表明，特定的基因组区域是假单胞菌（P. daedalea）的耐热性的原因，其中一些SNP属于编码区。这些发现表明该P. daedalea种群具有适应温度升高的遗传先决条件。这项研究还为开发高通量基因组工具提供了知识，以筛选种群内和种群间的变异，以通过辅助基因流和辅助迁移来利用或增强适应性。