Asynapsis in the salivary gland chromosomes ofDrosophila hydei

An investigation of the asynapsis phenomenon in salivary gland chromosomes ofDrosophila hydei was undertaken. Asynapsis was found to occur in fixed and stained as well as in surviving chromosomes.Frequency of asynapsis was found to be much higher in the X-chromosome than in any of the autosomes. The total asynapsis frequency of autosomes is slightly higher in females than in males. Among the four large autosomes, no consistent preference or sequence of frequency was encountered. In none of the chromosomes a preference of asynapsis for a certain region was found. Crowding of the cultures had no influence on frequency or distribution of non-pairing.In hybrids between wild stocks of different geographic origin a slightly higher asynapsis frequency, compared to the wild stocks was found.