Klingenberg C P, Leamy L J
University Museum of Zoology, Department of Zoology, Cambridge, United Kingdom.
Evolution. 2001 Nov 11;55(11):2342-52. doi: 10.1111/j.0014-3820.2001.tb00747.x.
We combine the methods of geometric morphometrics and multivariate quantitative genetics to study the patterns of phenotypic and genetic variation of mandible shape in random-bred mice. The data are the positions of 11 landmarks on the mandibles of 1,241 mice from a parent-offspring breeding design. We use Procrustes superimposition to extract shape variation and restricted maximum likelihood to estimate the additive genetic and environmental components of variance and covariance. Matrix permutation tests showed that the genetic and phenotypic as well as the genetic and environmental covariance matrices were similar, but not identical. Likewise, principal component analyses revealed correspondence in the patterns of phenotypic and genetic variation. Patterns revealed in these analyses also showed similarities to features previously found in the effects of quantitative trait loci and in the phenotypes generated in gene knockout experiments. We used the multivariate version of the breeders' equation to explore the potential for short-term response to selection on shape. In general, the correlated response is substantial and regularly exceeds the direct response: Selection applied locally to one landmark usually produces a response in other parts of the mandible as well. Moreover, even selection for shifts of the same landmark in different directions can yield dramatically different responses. These results demonstrate the role of the geometry and anatomical structure of the mandible, which are key determinants of the patterns of the genetic and phenotypic covariance matrices, in molding the potential for adaptive evolution.
我们结合几何形态测量学和多变量定量遗传学方法，研究随机繁殖小鼠下颌骨形状的表型和遗传变异模式。数据来自一个亲子繁殖设计中1241只小鼠下颌骨上11个地标点的位置。我们使用普氏叠加法提取形状变异，并使用限制最大似然法估计方差和协方差的加性遗传和环境成分。矩阵置换检验表明，遗传和表型以及遗传和环境协方差矩阵相似，但并不相同。同样，主成分分析揭示了表型和遗传变异模式的对应关系。这些分析中揭示的模式也与先前在数量性状基因座效应和基因敲除实验产生的表型中发现的特征相似。我们使用育种者方程的多变量版本来探索对形状选择的短期反应潜力。一般来说，相关反应很大，而且经常超过直接反应：局部应用于一个地标点的选择通常也会在下颌骨的其他部位产生反应。此外，即使对同一地标点在不同方向上的移动进行选择，也可能产生截然不同的反应。这些结果证明了下颌骨的几何形状和解剖结构在塑造适应性进化潜力方面的作用，而下颌骨的几何形状和解剖结构是遗传和表型协方差矩阵模式的关键决定因素。
