Climate change selects for heterozygosity in a declining fur seal population
Climate change selects for heterozygosity in a declining fur seal population
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DOI：
10.1038/nature13542
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发表时间：
2014-07-24
期刊：
影响因子：
64.8
通讯作者：
Hoffman, Joseph Ivan
中科院分区：
文献类型：
--
作者：
Forcada, Jaume;Hoffman, Joseph Ivan
全球环境变化预计将改变许多生物系统中的选择压力(1-3)，但量化选择变化所需的长期分子和生活史数据很少(4)。三十年来从南大西洋不断减少的南极毛海豹中收集的基于个体的数据提供了一个不同寻常的机会。在这里，气候变化减少了猎物的可获得性，并导致海豹出生体重显著下降。然而，招募进入繁殖种群的雌性的平均年龄和体型正在增加。我们发现，这类女性的杂合度(衡量个体内遗传变异的指标)明显高于她们未被征召的兄弟姐妹和她们自己的母亲。因此，在过去的二十年里，每一代繁殖的雌性杂合度增加了8.5%。然而，由于杂合性不会从母亲遗传给女儿，因此大量的杂合子优势不会从一代传到下一代，纯合子个体生存能力的下降导致种群数量下降。我们的结果提供了令人信服的证据，表明气候变化导致的选择正在加剧，对人口学以及表型和遗传变异产生了深远的影响。
Global environmental change is expected to alter selection pressures in many biological systems(1-3), but the long-term molecular and life history data required to quantify changes in selection are rare(4). An unusual opportunity is afforded by three decades of individual-based data collected from a declining population of Antarctic fur seals in the South Atlantic. Here, climate change has reduced prey availability and caused a significant decline in seal birth weight. However, the mean age and size of females recruiting into the breeding population are increasing. We show that such females have significantly higher heterozygosity (a measure of within-individual genetic variation) than their non-recruiting siblings and their own mothers. Thus, breeding female heterozygosity has increased by 8.5% per generation over the last two decades. Nonetheless, as heterozygosity is not inherited from mothers to daughters, substantial heterozygote advantage is not transmitted from one generation to the next and the decreasing viability of homozygous individuals causes the population to decline. Our results provide compelling evidence that selection due to climate change is intensifying, with far-reaching consequences for demography as well as phenotypic and genetic variation.