A multivariate analysis of dominance inDrosophila

Eleven wing measurements in twoDrosophila melanogaster lines (Canton and FLL) and their reciprocal crosses were analyzed by a multivariate technique in order to investigate changes in variability when dominance is manifested. FLL line was obtained by artificial selection for short wing applied on one measurement on the rightwing. Differences between left and right wing were observed in variabilities after selection. The comparison between F1 and parental populations shows that there is strong evidence for non-additivity which is manifested by a component of the variability due to multiple regression. This is interpreted as meaning that relationships between characters are affected in the heterozygote in a non-additive way, apparently due to interactions among the developmental patterns of the characters considered. It is suggested that a "character" should be defined in such a way as to include its developmental patterns, in order to achieve a better understanding of the dominance phenomenon.