Torpedo, is known to serve as a receptor for Gurken. Deficiencies of the torpedo gene is Drosophila cause ventralization of the embryo. In an experiment, the germ cell precursors from a wild type embryo were transplanted into embryos whose mother carried the torpedo mutation. Also, the reverse experiment, i.e., transplantation of germ cell precursors from torpedo mutants into wild type embryos was done. The torpedo deficient germ cells developed in a wild type female showed normal dorso-ventral axis, while the wild type germ cells developed in a torpedo deficient female showed ventralized egg.
Some of the following statements are drawn from the above experiments and some from known facts to understand the functioning of Torpedo.