THE BEHAVIOR OF NONHOMOLOGOUS CHROMOSOMAL ELEMENTS INVOLVED IN NONRANDOM ASSORTMENT IN DROSOPHILA MELANOGASTER

Abstract

Answers to the questions posed and certain other conclusions concerning the behavior of nonhomologous elements involved in nonrandom assortments in the female of Drosophila can be given: Nonrandom assortments of nonhomologues may be induced in high frequencies by the presence in the genome of 2 or more nonhomologous elements that lack homologous pairing partners. The equality of reciprocal classes that result from these assortments establishes that they are the result of meiotic segregations. The Y chromosome is not a necessary component of this system. When more than 2 such elements are present, competition for associations occur among them. Different elements have different degrees of attraction for a nonhomologue. The proximal heterochromatic regions of chromosomes are not entirely responsible for nonhomologous associations.