Singleton Alexandra L, Liu Megan H, Votzke Samantha, Yammine Andrea, Gibert Jean P
Department of Biology Duke University Durham North Carolina USA.
Ecol Evol. 2021 Dec 14;11(24):17810-17816. doi: 10.1002/ece3.8335. eCollection 2021 Dec.
Genetic diversity and temperature increases associated with global climate change are known to independently influence population growth and extinction risk. Whether increasing temperature may influence the effect of genetic diversity on population growth, however, is not known. We address this issue in the model protist system . We test the hypothesis that at temperatures closer to the species' thermal optimum (i.e., the temperature at which population growth is maximal, or ), genetic diversity should have a weaker effect on population growth compared to temperatures away from the thermal optimum. To do so, we grew populations of . with varying levels of genetic diversity at increasingly warmer temperatures and quantified their intrinsic population growth rate, . We found that genetic diversity increases population growth at cooler temperatures, but that as temperature increases, this effect weakens. We also show that a combination of changes in the amount of expressed genetic diversity (G) in , plastic changes in population growth across temperatures (E), and strong G × E interactions underlie this temperature effect. Our results uncover important but largely overlooked temperature effects that have implications for the management of small populations with depauperate genetic stocks in an increasingly warming world.
已知与全球气候变化相关的遗传多样性和温度升高会独立影响种群增长和灭绝风险。然而，温度升高是否会影响遗传多样性对种群增长的作用尚不清楚。我们在模式原生生物系统中解决了这个问题。我们检验了这样一个假设：与远离热最适温度的情况相比，在更接近物种热最适温度（即种群增长最大时的温度，或 ）时，遗传多样性对种群增长的影响应该更弱。为此，我们在逐渐升高的温度下培养了具有不同遗传多样性水平的 种群，并量化了它们的内禀种群增长率， 。我们发现遗传多样性在较凉爽的温度下会增加种群增长，但随着温度升高，这种影响会减弱。我们还表明， 中表达的遗传多样性量（G）的变化、温度间种群增长的可塑性变化（E）以及强烈的G×E相互作用共同构成了这种温度效应。我们的研究结果揭示了重要但在很大程度上被忽视的温度效应，这些效应对于在日益变暖的世界中管理遗传资源匮乏的小种群具有重要意义。
