The influence of hypotonic treatment on the morphology of meiotic stages II. Prophase of the first meiotic division of female mice up to dictyotene

The copy number of the mdg-1 mobile element was determined by biotinylated-DNA hybridization, in salivary gland chromosomes of inbred Drosophila melanogaster larvae from sib progenies. It appears that the lower the egg-to-adult survival (viability), the higher the mdg-1 copy number in the surviving larvae. This suggests a common regulation of the mdg-1 copy number and the viability under inbreeding.