The behavior of the fourth chromosome in Drosophila melanogaster Spermatogenesis

Meiotic Sex Chromosome Inactivation (MSCI) is a process of transcriptional silencing of the sex chromosomes in the early stages of meiosis in spermatogenesis. Recently, the IV chromosome of D. melanogaster (dot) was described as an ancient X chromosome. This finding suggests that possibly the IV chromosome has characteristic sequences used in regulations related to the sex chromosome, including regulations during meiosis. In order to verify the behavior and the activity of the IV chromosome during meiosis I, cytogenetic experiments (double immunofluorescence-FISH) were performed in meiotic cells of adult testis using different types of RNA polymerase II