College of Science and Engineering and ARCCOE for Coral Reef Studies, James Cook University, Townsville, Queensland, Australia.
Australian Institute of Marine Science, Townsville, Queensland, Australia.
Glob Chang Biol. 2021 Nov;27(22):5694-5710. doi: 10.1111/gcb.15829. Epub 2021 Sep 5.
Anthropogenic climate change is a rapidly intensifying selection pressure on biodiversity across the globe and, particularly, on the world's coral reefs. The rate of adaptation to climate change is proportional to the amount of phenotypic variation that can be inherited by subsequent generations (i.e., narrow-sense heritability, h ). Thus, traits that have higher heritability (e.g., h > 0.5) are likely to adapt to future conditions faster than traits with lower heritability (e.g., h < 0.1). Here, we synthesize 95 heritability estimates across 19 species of reef-building corals. Our meta-analysis reveals low heritability (h < 0.25) of gene expression metrics, intermediate heritability (h = 0.25-0.50) of photochemistry, growth, and bleaching, and high heritability (h > 0.50) for metrics related to survival and immune responses. Some of these values are higher than typically observed in other taxa, such as survival and growth, while others were more comparable, such as gene expression and photochemistry. There was no detectable effect of temperature on heritability, but narrow-sense heritability estimates were generally lower than broad-sense estimates, indicative of significant non-additive genetic variation across traits. Trait heritability also varied depending on coral life stage, with bleaching and growth in juveniles generally having lower heritability compared to bleaching and growth in larvae and adults. These differences may be the result of previous stabilizing selection on juveniles or may be due to constrained evolution resulting from genetic trade-offs or genetic correlations between growth and thermotolerance. While we find no evidence that heritability decreases under temperature stress, explicit tests of the heritability of thermal tolerance itself-such as coral thermal reaction norm shape-are lacking. Nevertheless, our findings overall reveal high trait heritability for the majority of coral traits, suggesting corals may have a greater potential to adapt to climate change than has been assumed in recent evolutionary models.
人为气候变化是对全球生物多样性，特别是对世界珊瑚礁的一种迅速加剧的选择压力。对气候变化的适应速度与后代可继承的表型变异量成正比（即狭义遗传力，h）。因此，具有较高遗传力（例如，h>0.5）的特征可能比遗传力较低的特征（例如，h<0.1）更快地适应未来的条件。在这里，我们综合了 19 种造礁珊瑚的 95 个遗传力估计值。我们的荟萃分析显示，基因表达指标的遗传力较低（h<0.25），光合作用、生长和白化的遗传力中等（h=0.25-0.50），与生存和免疫反应相关的指标的遗传力较高（h>0.50）。其中一些值高于其他分类群通常观察到的值，例如生存和生长，而其他值则更具可比性，例如基因表达和光合作用。遗传力不受温度的影响，但狭义遗传力估计值通常低于广义遗传力估计值，表明各性状之间存在显著的非加性遗传变异。性状遗传力也因珊瑚生活阶段而异，与幼虫和成虫相比，幼年珊瑚的白化和生长的遗传力通常较低。这些差异可能是由于对幼年珊瑚的先前稳定选择，也可能是由于生长和耐热性之间的遗传权衡或遗传相关性导致的进化受限。虽然我们没有发现遗传力在温度胁迫下降低的证据，但对热耐受性本身的遗传力的明确测试（例如珊瑚的热反应规范形状）是缺乏的。尽管如此，我们的研究结果总体上揭示了大多数珊瑚性状的高遗传力，这表明珊瑚可能比最近的进化模型所假设的更有潜力适应气候变化。
