Pigliucci M
Department of Botany, University of Tennessee, Knoxville 37996-1100, USA.
Heredity (Edinb). 1996 Nov;77 ( Pt 5):453-60. doi: 10.1038/hdy.1996.171.
Predictions of the evolutionary trajectory of reaction norms and interpretation of empirical results are usually based on two mathematically equivalent ways of partitioning phenotypic variance into its genetic, environmental, and interaction components: the genotype by environment interaction estimated by means of an analysis of variance, or the interenvironment genetic correlation (i.e. the genetic correlation between the expressions of the same trait in two environments). Both these quantities are supposed to indicate the amount of genetic variability for plasticity in natural population. I point out that not only are the qualitative predictions based on these statistical methods sometimes in conflict with each other, but that both may fail to predict rates of evolution and equilibria under some circumstances, because they ignore the details of the genetic machinery. It is shown that, ultimately, the only way to predict reliably the evolution of plasticity is actually to know its specific genetic basis and the genotypic constitution of the population, however inconvenient this may be from both theoretical and empirical standpoints. The discussion is framed in terms of a simple one-locus two-allele model that mimics the real case of the pennant/vestigial system describing plasticity of wing length to temperature in Drosophila melanogaster.
反应规范进化轨迹的预测以及实证结果的解释通常基于两种数学上等效的方法，即将表型方差划分为遗传、环境和交互成分：通过方差分析估计的基因型与环境的交互作用，或环境间遗传相关性（即同一性状在两种环境中的表达之间的遗传相关性）。这两个量都被认为可指示自然种群中可塑性的遗传变异性大小。我指出，基于这些统计方法的定性预测不仅有时相互冲突，而且在某些情况下两者都可能无法预测进化速率和平衡，因为它们忽略了遗传机制的细节。结果表明，最终，可靠预测可塑性进化的唯一方法实际上是了解其具体的遗传基础和种群的基因型组成，无论从理论还是实证角度来看这可能有多不便。讨论以一个简单的单基因座双等位基因模型展开，该模型模拟了描述黑腹果蝇翅长对温度可塑性的三角旗/残翅系统的实际情况。
