Specific Reactions of the Ovary to Interspecific Transplantation among Members of the Melanogaster Group of Drosophila.

HE transplantation of ovaries in Drosophila was realized for the first T time by EPHRUSSI and BEADLE (1935b), using the technique which they had devised and applied with such success to the transplantation of the eye discs and other anlagen. Their results showed that the ovaries of D. melamguster can be successfully implanted into male and female larvae of the same species, can become attached to the female genital ducts of the host, and can function almost as efficiently as the host ovaries themselves. In some cases as many as three ovaries were transplanted to a single female and developed successfully, together with the host ovaries. Furthermore, EPHRUSSI and BEADLE showed that interspecific transplants were possible, a t least in the case of simulans ovaries in melanogaster. These implants proved to be quite as successful as the homospecific ones, for simulans ovaries became attached to the genital ducts and functioned normally in a melanogaster host. It was obvious that by using this technique many crosses which are normally impossible could be attempted, since in most cross combinations no mating occurs for lack of sexual attraction or for other reasons. Studying the possibilities of such a technique was the first aim of the experiments presented here. The results of these experiments, however, brought evidence of some interspecific reactions of a particular kind, which axe limited to the ovary and depend, not so much on the general constitution of the species used, as on the action of certain genes. These phenomena seem to set an entirely new problem, the nature of which will be discussed in this paper. The experiments were originally begun by one of us (J. MONOD) with Dr. BORIS EPHRUSSI, but were carried to completion by both authors. Acknowledgment is made to Dr. EPHRUSSI for his part in the work and especially for his stimulating interest, and to Mr. C. W. CLANCY and Dr. G. W. BEADLE for consenting to the presentation of certain of their unpublished data.