Dominant male sterility in D. melanogaster has been associated with approximately 75% of translocations between the sex chromosomes and autosomes. The current model for male infertility suggests condensation of the sex chromosomes directed by an element in the centric heterochromatin silences X-linked genes earlier than the autosomes during spermatogenesis. By generating a collection of X-ray-induced translocations between the autosomes and X-chromosomes, we will locate breakpoints to map the heterochromatin site responsible for X chromosome regulation and use RNA-seq to determine if there are altered expression levels of either X-linked or autosomal genes during spermatogenesis. This will allow us to test the current models for sterilizing effects involving the X-autosome translocation and to further understand the underlying factors in male infertility.