DEGENERATING GYPSY RETROTRANSPOSONS IN A MALE-FERTILITY GENE ON THE Y-CHROMOSOME OF DROSOPHILA-HYDEI

During the evolution of the Y chromosome of Drosophila hydei, retrotra nsposons became incorporated into the lampbrush loop pairs formed by s everal of the male fertility genes on this chromosome. Although insert ions of retrotransposons are involved in many spontaneous mutations, t hey do not affect the functions of these genes. We have sequenced gyps y elements that are expressed as constituents of male fertility gene Q in the lampbrush loop pair Nooses. We find that these gypsy elements are all truncated and specifically lost those sequences that may inter fere with the continuity of lampbrush loop transcription. Only defecti ve coding regions are found within the loop. Gypsy is not transcribed in loops of many other Drosophila species harboring the family. These results suggest that any contribution of gypsy to the function of male fertility gene Q does not depend on a conserved DNA sequence.