Murren Courtney J, Pendleton Nicole, Pigliucci Massimo
Department of Botany.
Am J Bot. 2002 Apr;89(4):655-63. doi: 10.3732/ajb.89.4.655.
Phenotypic integration is a necessary characteristic of living organisms that results from genetic, developmental, and functional relationships among traits. The nature of these relationships can be influenced by the environment. We examined patterns of phenotypic integration of six species of rapid cycling Brassica and of Raphanus sativus within a phylogenetic context. Specifically, we tested the hypothesis that hybrid species show intermediate levels of integration in morphological and life-history characters compared to their putative parentals. We used matrix correlation tests to examine if cytogenetic relationships or ecological similarities among species partially explained the patterns of phenotypic integration. There was a significant negative relationship between the ecological and cytogenetic matrices, suggesting that more closely related species were ecologically dissimilar. However, neither ecological nor cytogenetic matrices significantly explained differences among species in the pattern of their phenotypic correlations. Set correlation analysis indicated that important traits within the modules and the strength of the correlations within modules differed across species. We also found that there were a greater number of significant correlations between modules than within modules. Hybrid species were more integrated (had greater number of significant trait correlations) than either of their parents, both within and between modules. However, univariate analyses of character means of the hybrid species were not significantly different from the combined mean of their putative parents for 5, 6, or 7 of the 11 phenotypic characters (for Brassica napus, B. juncea and B. carinata, respectively); for the remaining characters, the hybrids were more similar to one of the parents.
表型整合是生物体的一种必要特征，它源于性状之间的遗传、发育和功能关系。这些关系的性质会受到环境的影响。我们在系统发育背景下研究了六种快速循环的芸苔属植物和萝卜的表型整合模式。具体而言，我们检验了这样一个假设：与假定的亲本相比，杂交物种在形态和生活史特征方面表现出中等程度的整合水平。我们使用矩阵相关性检验来考察物种间的细胞遗传学关系或生态相似性是否部分解释了表型整合模式。生态矩阵和细胞遗传学矩阵之间存在显著的负相关关系，表示亲缘关系越近的物种在生态上差异越大。然而，生态矩阵和细胞遗传学矩阵均未显著解释物种间表型相关性模式的差异。集合相关性分析表明，模块内的重要性状以及模块内相关性的强度在不同物种间存在差异。我们还发现，模块间的显著相关性数量多于模块内。无论是在模块内还是模块间，杂交物种都比其任何一个亲本的整合程度更高（具有更多显著性状相关性）。然而，对于11个表型性状中的5个、6个或7个（分别对应甘蓝型油菜、芥菜型油菜和埃塞俄比亚芥），杂交物种性状均值的单变量分析与假定亲本的合并均值并无显著差异；对于其余性状，杂交物种与其中一个亲本更为相似。
