THE PROBLEM OF DOMINANT LETHALS IN Drosophila Melanogaster FEMALES

Publisher Website
Google Scholar
Abstract
A model is presented which explains the present data on dominant lethal mutations in D. melanogaster females. Under the assumption that any one of the 4 haploid nuclei (which result from the meiotic divisions) can function as the female pronucleus, the minimum requirements for a dominant lethal are the occurrence of an isochromatid break in each of 2 different bivalents, sister fusion of the broken chromatids, and the passage of the fused bivalents so produced to opposite poles at anaphase I. Under these conditions the female pronucleus will always receive an aneuploid chromosome complement. Multiple isochromatid breakage may require multiple events if the chromatin is diffuse, or a single event if the chromatin is compact. Evidence is presented to support the view that the female pronucleus is not predetermined.