Mutations affecting dosage compensation in Drosophila melanogaster: effects in the germline

Dosage compensation is the process by which the total amount of gene products of X-linked genes is equalized in females (2X;2A) and males (X;2A). The achievement of dosage compensation takes place at the transcriptional level. Mutations have been isolated that impair the dosage compensation process. These mutations are the male-specific lethals msl-1, msl-2, and mle, which have been analyzed in the somatic tissues. Our aim was to know whether these mutations affect the germline. For this purpose, pole cells homozygous for the male-specific lethal mutations were transplanted into wild-type host embryos, and we checked whether the mutant pole cells were capable of forming functional sperm. The results are as follows: the msl-1 and msl-2 genes are not needed in the germline, while the mle gene seems to be required for normal spermatogenesis.