Selmoni Oliver, Cleves Phillip A, Exposito-Alonso Moises
Department of Plant Biology, Carnegie Institution for Science, Stanford, CA 94305, USA.
Department of Embryology, Carnegie Institution for Science, Baltimore, MD 21218, USA.
bioRxiv. 2025 Aug 11:2024.03.25.586253. doi: 10.1101/2024.03.25.586253.
The dramatic decline of reef-building corals calls for a better understanding of coral adaptation to ocean warming. Here, we characterized genetic diversity of the widespread genus by building a genomic database of 595 coral samples from different oceanic regions-from the Great Barrier Reef to the Persian Gulf. Through genome-environment associations, we found that different species showed parallel evolutionary signals of heat-adaptation in the same genomic regions, pointing to genes associated with molecular heat shock responses and symbiosis. We then projected the present and the predicted future distribution of heat-adapted genotypes across reefs worldwide. Reefs projected with low frequency of heat-adapted genotypes display higher rates of decline, indicating a potential genomic vulnerability to heat exposure. Our projections also suggest a transition where heat-adapted genotypes will spread at least until 2040. However, this transition will likely involve mass mortality of entire non-adapted populations and a consequent erosion of genetic diversity. This genetic diversity loss could hinder the capacity of to adapt to the more extreme heatwaves projected beyond 2040. Genomic vulnerability and genetic diversity loss estimates can be used to reassess which coral reefs are at risk and their conservation.
造礁珊瑚的急剧衰退需要我们更好地了解珊瑚对海洋变暖的适应情况。在此，我们通过构建一个包含来自不同海洋区域（从大堡礁到波斯湾）的595个珊瑚样本的基因组数据库，对这个分布广泛的属的遗传多样性进行了表征。通过基因组与环境的关联分析，我们发现不同的物种在相同的基因组区域显示出平行的热适应进化信号，指向与分子热休克反应和共生相关的基因。然后，我们预测了全球珊瑚礁上热适应基因型的当前和未来分布情况。预测显示热适应基因型频率较低的珊瑚礁衰退速度更快，这表明其在热暴露方面存在潜在的基因组脆弱性。我们的预测还表明，至少到2040年，热适应基因型将出现扩散的转变。然而，这种转变可能会导致整个非适应种群的大量死亡，进而造成遗传多样性的丧失。这种遗传多样性的丧失可能会阻碍珊瑚适应2040年以后预计出现的更极端热浪的能力。基因组脆弱性和遗传多样性丧失的评估结果可用于重新评估哪些珊瑚礁面临风险及其保护情况。
