Ernande B, Clobert J, McCombie H, Boudry P
Centre de Recherche en Ecologie Marine et Aquaculture, CNRS-IFREMER, L'Houmeau, France.
J Evol Biol. 2003 May;16(3):399-414. doi: 10.1046/j.1420-9101.2003.00543.x.
We investigated genetic variability and genetic correlations in early life-history traits of Crassostrea gigas. Larval survival, larval development rate, size at settlement and metamorphosis success were found to be substantially heritable, whereas larval growth rate and juvenile traits were not. We identified a strong positive genetic correlation between larval development rate and size at settlement, and argue that selection could optimize both age and size at settlement. However, trade-offs, resulting in costs of metamorphosing early and large, were suggested by negative genetic correlations or covariances between larval development rate/size at settlement and both metamorphosis success and juvenile survival. Moreover, size advantage at settlement disappeared with time during the juvenile stage. Finally, we observed no genetic correlations between larval and juvenile stages, implying genetic independence of life-history traits between life-stages. We suggest two possible scenarios for the maintenance of genetic polymorphism in the early life-history strategy of C. gigas.
我们研究了太平洋牡蛎早期生活史性状的遗传变异性和遗传相关性。结果发现，幼虫存活率、幼虫发育率、附着时的大小以及变态成功率具有较高的遗传性，而幼虫生长率和幼体性状则不然。我们发现幼虫发育率与附着时的大小之间存在很强的正遗传相关性，并认为选择可以优化附着时的年龄和大小。然而，幼虫发育率/附着时的大小与变态成功率和幼体存活率之间的负遗传相关性或协方差表明，存在权衡，即早期和大型变态会产生成本。此外，附着时的大小优势在幼体阶段会随着时间消失。最后，我们观察到幼虫和幼体阶段之间没有遗传相关性，这意味着不同生活阶段的生活史性状在遗传上是独立的。我们提出了两种可能的情况来解释太平洋牡蛎早期生活史策略中遗传多态性的维持。
