Identification of cloned Y chromosomal DNA sequences from a lampbrush loop of Drosophila hydei

By recombinant DNA techniques, a Y chromosomal sequence of Drosophila hydei was isolated. This DNA sequence of 8.93-kilobase length is a member of a family of repetitive sequences located in the short arm of the Y chromosome. Tissue-specific transcripts complementary to the cloned sequence were found in testes RNA. In situ hybridization demonstrated that such transcripts are present in the lampbrush loop pair "nooses" in primary spermatocyte nuclei--a loop pair that is associated with the only fertility gene in the short arm of the Y chromosome.