Relative Fitness of a Third Chromosome Inversion in Drosophila Melanogaster

Abstract

SummaryExperiments with D. melanogaster were conducted to obtain information on the relative fitness of the structural heterozygote of a third chromosome inversion, In (3R)P, in five different genetic backgrounds.The results have shown that in all instances the inversion heterozygote was superior in fitness to both homozygotes and that the adaptive value of the chromosomal arrangement was conditioned by the genetic background.Estimates of 8 and t, the reduction in fitness of the standard and inversion homozygotes relative to the inversion heterozygote, were O· 25, 0'27, O· 33, O· 02, and 0·25,0·86,0·63,0·16, respectively, for each of the A, B, C, and D experimental populations, and § equalled 0·071 for the HL population.

High resolution electrophoretic variation at the esterase-6 locus in a natural population of Drosophila melanogaster

“…2). Viability effects are known to be associated with inversions (Nassar, 1968;Watanabe and Yamazaki, 1976), but in this study lines carrying the In(3L)P inversion, which was in gametic disequilibrium with class 4, did not differ significantly in viability from other lines. Voelker et a!.…”

Inversion polymorphisms in Japanese natural populations of Drosophila melanogaster.

“…The polymorphic inversions are often maintained in natural populations by balanc-ing selection due to heterosis. Heterokaryotype superiority in some inversion of Drosophila melanogaster has been reported by several workers (Watanabe andWatanabe 1973, 1977;Nassar 1968;Stalker 1976) . However, the present study could not show any significant excess of the heterokaryotypes in populations (Table 2) .…”

Frequency-Dependent Selection at the Payne Inversion in Drosophila melanogaster

“…Four wild type populations (A, B, C and D) described by Nassar (1968) were mated in a two-way cross and the resulting population was crossed to a laboratory line homozygous for the Payne inversion, In (3R)P. The resulting cross was maintained in the laboratory (in half pint bottles) for more than 45 generations as a large random mating population. Unless otherwise indicated, populations were kept under discrete non-overlapping generations and parents were allowed to lay eggs for three days before they were discarded.…”