Abstract
Asymmetry has been used as a measure of developmental stability for bilaterally symmetrical organisms. Most studies have failed to partition the genetic and environmental contributions to the asymmetry phenotype due to the limitations of the systems used or the shortcomings in experimental design. The Notch mutants of Drosophila melanogaster were used to study the genetic contribution to asymmetry for six different bristle characters. Asymmetry response was character specific for the mutants examined. For Nspl, N(Co), N264-47, Ax71d, Ax9B2, AxE2, 1(1)N(B) and nd2 significant asymmetry responses, relative to wildtype Canton-S, were observed for some characters. N60g11 and nd1 did not exhibit significant asymmetry for any of the characters examined. All of the mutants except N60g11 and nd1 showed thoracic bristle asymmetry. However, when asymmetry scores were pooled over the five bristle characters which individually exhibited fluctuating asymmetry, no significant differences were found between any genotypes. Therefore pooling asymmetry values across characters obscures the significant character specific asymmetry values observed. Thus caution is necessary when using the asymmetry phenotype of specific characters to draw organism wide conclusions about developmental stability.
