Malvezzi Alex J, Murray Christopher S, Feldheim Kevin A, DiBattista Joseph D, Garant Dany, Gobler Christopher J, Chapman Demian D, Baumann Hannes
School of Marine and Atmospheric Sciences, Stony Brook University Stony Brook, NY, USA.
Department of Marine Sciences, University of Connecticut Groton, CT, USA.
Evol Appl. 2015 Apr;8(4):352-62. doi: 10.1111/eva.12248. Epub 2015 Feb 13.
Assessing the potential of marine organisms to adapt genetically to increasing oceanic CO2 levels requires proxies such as heritability of fitness-related traits under ocean acidification (OA). We applied a quantitative genetic method to derive the first heritability estimate of survival under elevated CO2 conditions in a metazoan. Specifically, we reared offspring, selected from a wild coastal fish population (Atlantic silverside, Menidia menidia), at high CO2 conditions (∼2300 μatm) from fertilization to 15 days posthatch, which significantly reduced survival compared to controls. Perished and surviving offspring were quantitatively sampled and genotyped along with their parents, using eight polymorphic microsatellite loci, to reconstruct a parent-offspring pedigree and estimate variance components. Genetically related individuals were phenotypically more similar (i.e., survived similarly long at elevated CO2 conditions) than unrelated individuals, which translated into a significantly nonzero heritability (0.20 ± 0.07). The contribution of maternal effects was surprisingly small (0.05 ± 0.04) and nonsignificant. Survival among replicates was positively correlated with genetic diversity, particularly with observed heterozygosity. We conclude that early life survival of M. menidia under high CO2 levels has a significant additive genetic component that could elicit an evolutionary response to OA, depending on the strength and direction of future selection.
评估海洋生物在基因上适应海洋二氧化碳水平上升的潜力，需要诸如海洋酸化（OA）条件下与适应性相关性状的遗传力等代理指标。我们应用了一种定量遗传学方法，得出了后生动物在高二氧化碳条件下生存的首个遗传力估计值。具体而言，我们从野生沿海鱼类种群（大西洋银汉鱼，Menidia menidia）中选取后代，在高二氧化碳条件（约2300微巴）下从受精饲养至孵化后15天，与对照组相比，这显著降低了存活率。对死亡和存活的后代以及它们的亲本进行定量采样并进行基因分型，使用八个多态微卫星位点，以重建亲子谱系并估计方差成分。与无亲缘关系的个体相比，有亲缘关系的个体在表型上更为相似（即在高二氧化碳条件下存活时间相似），这转化为一个显著非零的遗传力（0.20±0.07）。母体效应的贡献出人意料地小（0.05±0.04）且不显著。重复样本中的存活率与遗传多样性呈正相关，特别是与观察到的杂合度。我们得出结论，在高二氧化碳水平下，大西洋银汉鱼的早期生命存活率具有显著的加性遗传成分，这可能引发对海洋酸化的进化响应，具体取决于未来选择的强度和方向。
