Development of Eye Colors in Drosophila: Extraction of the Diffusible Substances Concerned

Abstract

The development of eye color in Drosophila is known to involve special diffusible substances [1,2]. A genetically vermilion (v) eye will develop wild-type eye color if it is supplied with v+ substance by transplantation or by injection of body fluid of wild type flies. Similarly a genetically cinnabar (cn) eye will develop the color characteristic of wild type if it is supplied with cn+ substance. The present paper summarizes preliminary experiments made to learn something of the nature of the two substances just mentioned. During the course of our studies, Ephrussi and Harnly [3] have shown that pupal fluid can be freed of living cells by freezing in liquid air without destroying the v+ and cn+ substances. Khouvine, Ephrussi and Harnly [4] have shown further that these substances can be extracted from Calliphora pupae with 95 per cent alcohol-ether mixtures and with 95 per cent alcohol but not with pure ether. They conclude that these substances are not proteins or enzymes, a conclusion confirmed by our work.