Puffing in salivary gland chromosomes of picture-winged Hawaiian Drosophila

A portion of the X chromosome was examined for puffing activity shortly before puparium formation in several species of Hawaiian Drosophila. A large puff was induced by incubating excised salivary glands with ecdysone. In two of the seven species studied, the region in question has been moved by inversion to a new position relative to the banding sequence in the other species, but the reaction to ecdysone remained unchanged. Another puff, not affected by short term incubations with ecdysone, displayed different degrees of activity in some homosequential species, affording a cytological means for distinguishing these species.