Complex inheritance of male courtship song characters in Drosophila virilis.

We analyzed the inheritance of two male courtship song characters, number of pulses in a pulse train, and length of a pulse train in Drosophila virilis. Biometric analyses of song differences among 16 crosses over three generations (parental and reciprocal F1, F2, and backcrosses) were performed using two different approaches. The joint scaling test revealed significant additive and dominance components, and also significant additive interaction between maternal and progeny genotypes. The direction of dominance was toward shorter and denser pulses in D. virilis. In addition, planned comparisons (contrast analyses of variance) between different generations revealed significant Y chromosomal and transient maternal factors and their interactions, with all other factors contributing to differences in the means of song characters. These results suggest that the genetic basis of courtship song characters in D. virilis is primarily of autosomal polygenic nature, with small but significant Y chromosomal and nonchromosomal maternal effects.