Autosomal mutations that interfere with sex determination in somatic cells of Drosophila have no direct effect on the germline

In Drosophila, mutations at the transformer-2, the double-sex, or the intersex loci interfere with the normal sexual development of somatic cells. In order to study the effect of mutations at these loci on germ cell development, mutant germ cells were introduced into normal female or normal male gonads either by pole cell transplantation or by induced mitotic recombination, and their ability to give rise to functional gametes was tested. In contrast to the effects seen in mutant somatic cells, the mutant germ cells ( dsx dsx, dsx^D +, dsx^d dsx, tra-2 tra-2, ix ix) developed normally according to their chromosomal sex, and no sexual transformations of germ cells were observed. In combination with the results of J. L. Marsh and E. Wieschaus (1978, Nature (London) 272, 249-251) concerning the transformer locus, it seems that the four autosomal loci known to be involved in sex determination of somatic cells have no important role in the sexual development of the germline. The results are discussed with respect to sex determination in the germline of Drosophila and are compared to observations made on similar mutations in other animal species.