Analysis of dominance for competitive ability in Drosophila melanogaster

In these experiments the genetic basis of larval competition in Drosophila melanogaster was investigated. Competitive ability was defined by a series of regression coefficients relating larval performance to their mono- and duo-culture densities. Sixteen inter-related F1 hybrids were individually compared with their parents, revealing the presence of large amounts of dominance and heterosis for the various competitive parameters, all directed towards improved competitive ability. Analysis of the F1 hybrids amongst themselves revealed that most of the heterosis was due to either interchromosomal interaction, or the complementing action of haploid autosomes and relatively little was due to any specific interaction between the homologues. The relevance of these results to the current understanding of heterosis is discussed.