表型可塑性变异的生态-发育机制及其进化意义

Phenotypic plasticity: Eco-Devo and evolution

表型可塑性赋予生物个体在不同环境条件下通过产生不同表型来维持其适合度的能力。研究结果显示多数可塑性变异的产生是基于对环境变异信号的响应、改变基因表达式样并调整发育轨迹的结果,表观遗传调控体系在基因选择性表达和可塑性变异的跨世代传递过程中发挥了重要作用。不同物种和种群对环境变化的敏感性、发生可塑性变异的能力以及可塑性反应模式不尽相同,预示着控制可塑性能力并独立于控制性状的可塑性基因的存在,这些基因是直接响应环境信号并控制表型表达的调控基因。表型可塑性不仅是物种适应性进化的一个重要方面,也是选择进化的产物,物种的表型可塑性变异对其生态适应和进化模式有深远的影响。

Phenotypic plasticity refers to the ability of an organism to alter its physiology/morphology/behavior in response to changes in environmental conditions. Although encompassing various phenomena spanning multiple levels of organization, most plastic responses seem to take place by altering gene expression and eventually altering ontogenetic trajectory in response to environmental variation. Epigenetic modifications provide a plausible link between the environment and alterations in gene expression, and the alterations in phenotype based on environmentally induced epigenetic modifications can be inherited transgenerationally. Even closely related species and populations with different genotypes may exhibit differences in the patterns and the extents of plastic responses, indicating the wide existence of plasticity genes which are independent of trait means and directly respond to environmental stimuli by triggering phenotypic changes. The ability of plasticity is not only able to affect the adaptive evolution of species significantly, but is also an outcome of evolutionary processes. Therefore, phenotypic plasticity is a potentially important molder of adaptation and evolution.