Genomic determinants of coral heat tolerance across latitudes--RAD data. Acropora millepora

As global warming progresses, reef-building corals could avoid local population declines through “genetic rescue” involving exchange of heat-tolerant genotypes across latitudes, but only if latitudinal variation in thermal tolerance is heritable. Here we show up to ten-fold increase in survival of the coral larvae under heat stress when their parents come from a lower latitude warmer location. Larval heat tolerance was associated with heritable differences in expression of oxidative, extracellular, transport and mitochondrial functions that signified the lack of baseline stress. Finally, several genomic regions strongly responded to selection for heat tolerance in inter-latitudinal reciprocal crosses. Taken together, our results demonstrate that variation in coral heat tolerance across latitudes has a strong genetic basis and could serve as raw material for natural selection.

随着全球变暖持续加剧，造礁珊瑚（reef-building corals）或可通过跨纬度交换耐热基因型（heat-tolerant genotypes）的“遗传拯救（genetic rescue）”策略避免局地种群衰退，但该策略的实施前提是耐热性的纬度差异具有可遗传性。本研究发现，当珊瑚幼虫的亲本来自低纬度温暖海域时，其在热胁迫（heat stress）下的存活率最高可提升10倍。幼虫的耐热性与氧化应激、细胞外功能、转运功能及线粒体功能的可遗传表达差异显著相关，这类功能差异提示幼虫未受基础胁迫。此外，在跨纬度正反交（reciprocal crosses）实验中，多个基因组区域对耐热性选择产生了强烈响应。综上，本研究结果证实，珊瑚耐热性的纬度差异具有坚实的遗传基础，可作为自然选择的遗传原材料。