Genetic variation in responses to a settlement cue and elevated temperature in the reef-building coral Acropora millepora
Genetic variation in responses to a settlement cue and elevated temperature in the reef-building coral Acropora millepora
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DOI：
10.3354/meps08208
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发表时间：
2009-01-01
影响因子：
2.5
通讯作者：
Matz, Mikhail V.
中科院分区：
文献类型：
--
作者：
Meyer, Eli;Davies, Sarah;Matz, Mikhail V.
造礁珊瑚受到全球气候变化导致的海洋表面温度上升的威胁。珊瑚能否适应世代不断升高的温度，在一定程度上将取决于热生理和扩散潜力的可遗传变异，这可能成为自然选择的原材料。为了研究这种变异是否存在于珊瑚种群中，并建立一个框架来识别所涉及的珊瑚特有的遗传因素，我们在分枝珊瑚Acropora millepora的3个不同遗传群体之间进行了受控杂交。我们比较了幼虫家族(在这个物种中天生缺乏共生体)的几个生理特征，并观察到几乎每个案例的家族之间的差异。利用在标准温度和高温下培养的幼虫，我们测量了蛋白质含量的发育性下降和候选热反应基因的表达。我们使用体内线粒体酶活性测试来评估个体幼虫对温度变化的代谢反应。我们还比较了来自不同家庭的幼虫对自然定居线索的反应性，以获得对远程传播潜力的洞察。对总表型变异分量的划分证实了沉降率和β-γ晶体蛋白表达存在加性遗传效应，而线粒体Q(10)的变异以及肌动蛋白和热休克蛋白16的表达是由非加性效应驱动的。在这里分析的少数家庭中观察到的表型差异表明，自然珊瑚种群中存在相当大的可遗传变异，这支持了对气候变化做出有效适应性反应的可能性。
Reef-building corals are threatened by increasing sea surface temperatures resulting from global climate change. Whether corals can adapt to increasing temperatures over the course of generations will depend in part on heritable variation in thermal physiology and dispersal potential, which may serve as the raw material for natural selection. To investigate whether such variation exists in coral populations, and build a framework for identifying the coral-specific genetic factors involved, we performed controlled crosses between 3 genetically distinct colonies of the branching coral Acropora millepora. We compared the families of larvae (which in this species naturally lack symbionts) for several physiological traits, and observed between-family differences in nearly every case. Using larvae cultured at standard and elevated temperatures, we measured the developmental decrease in protein content and the expression of candidate heat response genes. We used an in vivo assay for mitochondrial enzyme activity to evaluate the metabolic response to temperature changes in individual larvae. We also compared the responsiveness of larvae from different families to a natural settlement cue to gain insights into long-range dispersal potential. Partitioning the components of total phenotypic variance confirmed the existence of additive genetic effects for settlement rates and beta gamma-crystallin expression, while variance in mitochondrial Q(10) and the expression of actin and Hsp16 were driven by non-additive effects. The phenotypic variance observed among the small number of families analyzed here suggests the existence of considerable heritable variation in natural coral populations, which supports the possibility of effective adaptive responses to climate change.