NONRANDOM ASSORTMENT IN PRIMARY NONDISJUNCTION IN DROSOPHILA MELANOGASTER

Abstract

Data for the primary nondisjunction of 5 sex-linked genotypes with one or more autosomal inversion-translocation complexes are presented along with data for several of the sex-linked inversion genotypes with either a translocation or an inversion. The results indicate that the mere presence of a translocation is not sufficient to bring about primary nondisjunction, even though the translocation contains inverted segments. The exceptional females receive either the translocation or the inversion depending on the type of translocation used, while nearly all the males receive the other. The explanation is based on the assumption of non-homologous pairing between the 2d chromosomes and X chromosomes.