Intercalary heterochromatin in the polytene chromosomes of Drosophila auraria.

Abstract

The distribution of intercalary heterochroatin in the salivary gland polytene chromosomes of Drosophila auraria is presented in these reports, as revealed by the tendency of certain regions to pair ectopically, and by the existence of weak points. The two well-formed Balbiani rings, which are known to exist in this species, and the largest early ecdysone puff 73B, which corresponds to the puff 75B of D. melanogaster, seem to involve intercalary heterochromatin. Several pairings of nucleolar chromatin with certain chromosomal bands, as well as similarities in the intercalary heterochromatin distribution between D. auraria and D. melanogaster, are also presented.