Experiments on the Effects of Homozygosity and Heterozygosity on the Rate of Development in Drosophila Melanogaster

Abstract

CHART 1.-Synthesis of strains used in the 1957 series of experiments. Isolated chromosomes, with regard to which the strains were rendered isogenic, are drawn in heavy lines. Females were made homozygous for one w containing X chromzsome as indicated in generation 1. Other females were made homozygous for a set of the two long autosomes containing wild type genes as indicated in generation 4. The chart shows how the genz w was substituted by other w alleles (collectively named w"), and how these were combined with the set of isogenous autosomes. Apart from w (locus 1.5) and its alleles, the following sex-linked marker genes were used: ec ( 5 . 5 ) , ct (20.0), U (33.0), f (56.7). The symbol yf refers to double attached XXY females homozygous for y and f. M5, CyL, and D are symbols for crossing over inhibiting dominant markers.

The estimation of generation interval in experimental populations ofDrosophila

“…Considering the estimation for D. melanogaster, D. simulans certainly provides the high density conditions of the population cage or bottle, but it is not known to what extent these conditions are similar to those in a pure D. melanogaster population. Even within species, there is evidence that the viability and adaptive values of genotypes are dependent on what other genotypes are co-existing with them and on their frequencies (Levene, Pavlovsky & Dobzhansky, 1954Lewontin, 1955;Spiess, 1957;Bonnier, Jonsson & Ramel, 1959;Parsons, 1959). As D. simulans v is rapidly eliminated from a population by D. melanogaster Oregon-R-C when the two are placed in competition (Claringbold & Barker, 1961), the competition provided by D. simulans is presumably of a lower order than that within a pure D. melanogaster population.…”

Experiments on Hybrid Superiority in Drosophila Melanogaster. I. Egg Laying Capacity and Larval Survival

“…BONNIER. JONSSON and RAMEL (1959) showed that the time span from egg hatching to eclosion was, in Drosophila melanogaster, shorter for larvae which were heterozygous for the two long autosomes than for those who were homozygous for these chromosmes.…”