Winn A A
Department of Biological Science, Florida State University, Tallahassee, FL, USA.
J Evol Biol. 2004 Sep;17(5):1073-83. doi: 10.1111/j.1420-9101.2004.00740.x.
Estimates of the form and magnitude of natural selection based on phenotypic relationships between traits and fitness measures can be biased when environmental factors influence both relative fitness and phenotypic trait values. I quantified genetic variances and covariances, and estimated linear and quadratic selection coefficients, for seven traits of an annual plant grown in the field. For replicates of 50 paternal half-sib families, coefficients of selection were calculated both for individual phenotypic values of the traits and for half-sib family mean values. The potential for evolutionary response was supported by significant heritability and phenotypic directional selection for several traits but contradicted by the absence of significant genetic variation for fitness estimates and evidence of bias in phenotypic selection coefficients due to environmental covariance for at least two of the traits analysed. Only studies of a much wider range of organisms and traits will reveal the frequency and extent of such bias.
当环境因素同时影响相对适合度和表型性状值时，基于性状与适合度测量之间的表型关系对自然选择的形式和强度进行的估计可能会产生偏差。我对一种一年生植物在田间生长的七个性状的遗传方差和协方差进行了量化，并估计了线性和二次选择系数。对于50个父本半同胞家系的重复样本，计算了性状的个体表型值和半同胞家系平均值的选择系数。几个性状存在显著的遗传力和表型定向选择，这支持了进化响应的可能性，但适合度估计缺乏显著的遗传变异，并且至少在两个分析的性状中存在由于环境协方差导致的表型选择系数偏差的证据，这与进化响应的可能性相矛盾。只有对更广泛的生物体和性状进行研究，才能揭示这种偏差的频率和程度。
