Figure 1. Profiling of the histone H3K4me2 modification in the Drosophila testis.

(A) Schematic of male germline stages in Drosophila. Germline stem cells (GSCs, fuschia) are located in the apical tip of the testis. After an asymmetric division a progeny spermatogonium (purple) undergoes four rounds of mitotic divisions. After one last S phase cells grow over ~3 days as spermatocytes (blue, light green, dark green) before meiosis (red). Post-meiotic differentiation produces mature sperm (black) with elongated nuclei. Somatic cell types of the testis are not shown. (B–E) Distribution of the H3K4me2 modification in testes from bam mutants, from aly mutants, from wildtype animals, and from wing imaginal discs. (B) H3K4me2 around the GSC-expressed nanos gene. Neighboring genes show peaks in all samples, while low signal across nanos is highest in testes from bam mutants, and apparent in all three testes samples. (C) H3K4me2 around the spermatocyte-expressed loopin-1 gene. H3K4me2 signal appears in aly mutant samples (which contain early spermatocytes) and reach high levels in wildtype testes (which include later stages of spermatogenesis). (D) H3K4me2 around the meiotically expressed genes Mst36Fa and Mst36Fb genes. Signal across these genes only appears in wildtype testes. (E) H3K4me2 around the abd-A and Abd-B genes, which are expressed in somatic cells of the testis.