Open AccessVariation in persistency of a lethal mutant in populations of Drosophila melanogaster
Author(s) -
RASMUSON MARIANNE
Publication year - 1970
Publication title -
hereditas
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.819
H-Index - 50
eISSN - 1601-5223
pISSN - 0018-0661
DOI - 10.1111/j.1601-5223.1970.tb02308.x
Subject(s) - biology , genetics , heterozygote advantage , cage , offspring , drosophila melanogaster , selection (genetic algorithm) , heterosis , gene , genotype , botany , mathematics , combinatorics , hybrid , pregnancy , artificial intelligence , computer science
The persistency of a dominant suppressor of cherry, Su‐w ch (II–4.0), lethal in homozygous condition, was studied in cage populations which were homozygous for w ch . It was found to be eliminated a little slower than is expected for a recessive lethal gene, but the equilibrium gene frequency was below 0.05. A stochastic experiment was performed by following 30 lines of 4♀♀X4♂♂ during 19 generations. The lines were started with +/ Su heterozygotes from one of the cage populations. In subsequent generations the parents were randomly selected. Analysis of the offspring in different family types revealed a higher productivity of +/ Su males, especially in combination with +/+ females. The relation between q and Δq gave some indications of frequency‐dependent selection. The observed distribution of gene frequencies in generations 4–19 was compared with random number simulations. The best correspondence was obtained with a selective value of 0.85 for the +/+ genotype. Four of the lines still segregated for Su at the end of the stochastic experiment. New cage populations were set up with descendants from these lines. They established themselves at an equilibrium gene frequency of 0.13–0.15. The unfixed lines were thus not a random sample from the 30 initial lines, and a between‐line selection for increased heterosis must be assumed.