Department of Biology, Hopkins Marine Station of Stanford University, Pacific Grove, CA 93950, USA.
School of Natural Sciences, California State University, Monterey Bay, Seaside, CA 93955, USA.
Sci Adv. 2017 Nov 1;3(11):e1701413. doi: 10.1126/sciadv.1701413. eCollection 2017 Nov.
Population genomic surveys suggest that climate-associated genetic variation occurs widely across species, but whether it is sufficient to allow population persistence via evolutionary adaptation has seldom been quantified. To ask whether rapid adaptation in reef-building corals can keep pace with future ocean warming, we measured genetic variation at predicted warm-adapted loci and simulated future evolution and persistence in a high-latitude population of corals from Rarotonga, Cook Islands. Alleles associated with thermal tolerance were present but at low frequencies in this cooler, southerly locality. Simulations based on predicted ocean warming in Rarotonga showed rapid evolution of heat tolerance resulting in population persistence under mild warming scenarios consistent with low CO emission plans, RCP2.6 and RCP4.5. Under more severe scenarios, RCP6.0 and RCP8.5, adaptation was not rapid enough to prevent extinction. Population adaptation was faster for models based on smaller numbers of additive loci that determine thermal tolerance and for higher population growth rates. Finally, accelerated migration via transplantation of thermally tolerant individuals (1 to 5%/year) sped adaptation. These results show that cool-water corals can adapt to warmer oceans but only under mild scenarios resulting from international emissions controls. Incorporation of genomic data into models of species response to climate change offers a promising method for estimating future adaptive processes.
种群基因组调查表明，与气候相关的遗传变异广泛存在于物种中，但它是否足以通过进化适应来维持种群的生存，这一点很少被量化。为了研究造礁珊瑚是否能快速适应未来的海洋变暖，我们测量了来自库克群岛拉罗汤加岛的珊瑚种群中预测的温暖适应基因座的遗传变异，并对其未来的进化和生存进行了模拟。在这个较凉爽、偏南的地方，与耐热性相关的等位基因虽然存在，但频率较低。基于拉罗汤加岛预测的海洋变暖的模拟显示，耐热性的快速进化导致了种群在轻度变暖情景下的持续存在，这与低 CO 排放计划（RCP2.6 和 RCP4.5）一致。在更严重的情景下（RCP6.0 和 RCP8.5），适应速度不够快，无法防止灭绝。对于基于决定耐热性的少数加性基因座的模型和种群增长率较高的模型，种群适应性的进化速度更快。最后，通过移植耐热个体（每年 1%至 5%）加速迁移，从而加速了适应过程。这些结果表明，冷水珊瑚可以适应更温暖的海洋，但只有在国际排放控制下产生的温和情景下才可以。将基因组数据纳入物种对气候变化的反应模型是估计未来适应过程的一种很有前途的方法。
