The effect of population density on the elimination dynamics of a recessive lethal mutation l(2)M167 DTS from experimental populations of Drosophila melanogaster

Abstract

Dynamics of the elimination of the temperature-sensitive lethal mutation l(2)M167 DTS from experimental populations of Drosophila melanogaster under permissive conditions (25 ° C) was studied. We have shown a rapid elimination of the mutation from the populations, selection for fitness of heterozygous individuals, association of the selection with high larval density and with the direction of the cross that had produced the founder males of the l(2)M167 DTS /+ population, and the effect of relative competitive ability of l(2)M167 DTS /+ males on the efficiency of the mutation introduction. Modification systems were shown be involved in fitness selection under conditions of high larval density. GENERAL GENETICS

Determination of Fitness Components of Flies Bearing the Recessive Lethal l(2)M167 DTS Mutation with Dominant Heat Sensitivity in Artificial Drosophila melanogaster Populations

“…The change in selection intensity determined from the precise frequencies of the l167 mutation [12,13] and detected by the applied model in population 4 argues for the latter explanation, at least, concerning this population. Nevertheless, the fact of sharp acceleration of selection against the mutation starting from the second generation formally disagrees with the notion of positive selection for fitness of individuals heterozygous for the mutation.…”

“…Experiments were performed with D. melanogaster stocks described in [12]: l167 / Cy , Cy / Pm , and D-32. Heterozygous males l167 / Cy obtained by crosses l167 / Cy × +/+(both directions) were introduced into experimental populations.…”

“…The method involves numerical solution of the model and description of the range of admissible values of specified fitness components with regard to reasonable limitations imposed on some components, e.g., according to the results of preliminary estimation of the variability ranges of these components. The values of fitness components were determined in [8][9][10][11][12]. The model was also modified to fit the case of asymmetry related to the limited fertility of females heterozygous for the mutation.…”

Recurrent model of the dependence of a recessive lethal mutation on fitness components and its solution

“…(11) transforms to 0, hence (13) As, due to symmetry of model 2, f 0 (q 1 , q 2 , s, w, v) = m 0 (q 1 , q 2 , w, s, v), the further rearrangements will be done only for f 0 . The following important statements (proved in Appendix 1) hold.…”

“…A number of problems, related to strong selection against the genotype examined, require estimation of fitness components for the mutation in few generations [13]. In the present work, we show that the solution of the model accounting for five fitness components [12] is based on the erroneous assumption on the uniqueness of the model solution for the genotype frequency sample in several generations; modify the model to account for differential female fecundity under conditions of limited food resources; and propose a numerical solution of the model determining the region of possible solutions for the fitness components with precision depending on restrictions on some components.…”