Masel J
Department of Biological Sciences, Stanford, CA, USA.
J Evol Biol. 2004 Sep;17(5):1106-10. doi: 10.1111/j.1420-9101.2004.00739.x.
Genetic assimilation occurs when an acquired trait loses dependency on its environmental trigger and becomes an inherited trait. According to the standard quantitative genetic model for genetic assimilation, the trait is determined by the contributions of multiple genes. Trait expression occurs at a lower threshold with the trigger. Selection for the trait in the presence of the trigger increases the frequency of the trait-determining alleles. Eventually these alleles become frequent enough to breach the higher threshold for expression in the absence of the trigger. This loss of dependence on the trigger signifies genetic assimilation. Here I show that genetic assimilation can occur in the absence of selection for the trait in an evolutionary simulation of a gene network model. This contradicts the prediction of the standard quantitative genetic model, but is consistent with an explanation in terms of the canalization heuristic.
当一个获得性性状失去对其环境触发因素的依赖并成为一种遗传性状时，就会发生遗传同化。根据遗传同化的标准数量遗传模型，该性状由多个基因的贡献决定。在有触发因素的情况下，性状表达发生在较低阈值。在有触发因素时对该性状进行选择会增加决定性状的等位基因的频率。最终，这些等位基因变得足够常见，以至于在没有触发因素的情况下突破了更高的表达阈值。对触发因素的这种依赖性丧失标志着遗传同化。在这里，我表明在基因网络模型的进化模拟中，在没有对性状进行选择的情况下也可以发生遗传同化。这与标准数量遗传模型的预测相矛盾，但与基于稳态启发法的解释一致。
