GENOTYPE-ENVIRONMENT INTERACTION AND THE EVOLUTION OF PHENOTYPIC PLASTICITY
GENOTYPE-ENVIRONMENT INTERACTION AND THE EVOLUTION OF PHENOTYPIC PLASTICITY
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DOI：
10.2307/2408649
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发表时间：
1985-01-01
期刊：
影响因子：
3.3
通讯作者：
LANDE, R
中科院分区：
文献类型：
--
作者：
VIA, S;LANDE, R
对环境空间变异的研究主要集中在如何保持遗传变异上。许多单基因座遗传模型已经解决了这个问题，但由于几个原因，这些模型不能直接适用于数量(多基因)性状。一个原因是，对于连续变化的特征，在不同环境中表达的平均表型的进化(反应的标准)也是令人感兴趣的。目前的数量遗传模型描述了表型反应对环境的进化，也被称为表型可塑性(Guss，1947)，并说明了反应的标准(SchMalhausen，1949)如何通过选择来塑造。这些模型利用基因-环境互作和遗传相关性之间存在的统计关系来描述粗粒环境中软选择和硬选择下平均表型的进化。正如单个环境中性状之间的遗传相关性可以限制对同时选择的反应一样，在两个环境中表达的性状状态之间的遗传相关性也可以限制反应。除非环境间的遗传相关性是.+-。1、多基因变异耗尽，或存在可塑性代价；在二元适应度函数下的泛生态种群最终将在每个环境中获得给定性状的最优平均表型。极高的正相关或负相关会大大减缓进化的速度，并可能在最终获得最佳关节表型之前，在一个环境中产生暂时的适应不良。在硬选择和软选择下的进化轨迹是不同的；在硬选择中，初始平均适应度最高的环境对交配池的贡献最大。在硬选择和软选择中，在稀有环境中朝着最优方向进化的速度比在普通环境中慢得多。一个细分的模型表明，移民限制可以促进当地适应。除非没有迁移或讨论的泛游者群体的特殊情况之一成立，否则反应规范的地理差异将不会保持在平衡状态。讨论了这些结果对解释自然种群表型变异的空间格局的意义。
Studies of spatial variation in the environment have primarily focused on how genetic variation can be maintained. Many 1-locus genetic models have addressed this issue, but, for several reasons, these models are not directly applicable to quantitative (polygenic) traits. One reason is that for continuously varying characters, the evolution of the mean phenotype expressed in different environments (the norm of reaction) is also of interest. The present quantitative genetic models describe the evolution of phenotypic response to the environment, also known as phenotypic plasticity (Gause, 1947), and illustrate how the norm of reaction (Schmalhausen, 1949) can be shaped by selection. These models use the statistical relationship which exists between genotype-environment interaction and genetic correlation to describe evolution of the mean phenotype under soft and hard selection in coarse-grained environments. Just as genetic correlations among characters within a single environment can constrain the response to simultaneous selection, so can a genetic correlation between states of a character which are expressed in 2 environments. Unless the genetic correlation across environments is .+-. 1, polygenic variation is exhausted, or there is a cost to plasticity; panmictic populations under a bivariate fitness function will eventually attain the optimum mean phenotype for a given character in each environment. Very high positive or negative correlations can substantially slow the rate of evolution and may produce temporary maladaptation in one environment before the optimum joint phenotype is finally attained. Evolutionary trajectories under hard and soft selection an differ; in hard selection, the environments with the highest initial mean fitness contribute most individuals to the mating pool. In both hard and soft selection, evolution toward the optimum in a rare environment is much slower than it is in a common one. A subdivided model reveals that migration restriction can facilitate local adaptation. Unless there is no migration or one of the special cases discussed for panmictic populations holds, no geographical variation in the norm of reaction will be maintained at equilibrium. Implications of these results for the interpretation of spatial patterns of phenotypic variation in natural populations are discussed.