Chiasmata in spermatocytes of Drosophila melanogaster

Abstract

On the basis of chromosome behaviour in three strains of Drosophila melanogaster males—a wild-type strain, a translocation heterozygote strain and a double translocation strain—it is concluded that the cytologically detected apparent chiasmata in the autosomes are only surface associations of homologous chromosomes and do not involve exchange of chromosome material. Such chiasma-like associations occur also between non-homologous chromosomes. The stainable, Feulgen-positive material of the chromosomes is thought to be responsible for the surface associations.