Nucleic acid synthesis in Rhynchosciara polytene chromosomes : effects of ecdysterone

In order to enhance and to stimulate DNA synthesis, ecdysterone, a derivative of the insect hormone ecdysone, was injected into young (30-day old) fourth instar Rhynchosciara hollaenderi larvae. At this stage of development, normal larvae show very low levels of DNA synthesis in the salivary gland chromosomes. Autoradiography was used to measure DNA synthesizing activity in the tissues analyzedEcology, Evolution and Behavio