Phases of Sex Chromosome Inactivation inOncopeltus FasciatusandPyrrhocoris Apterus(Insecta, Heteroptera)

Open Access
Publisher Website
Google Scholar
Abstract
Sex chromosomes in Oncopeltus fasciatus and Pyrrhocoris apterus are heterochromatic and transcriptionally inactive in well-defined phases of development. In Oncopeltus, which has the XX/XY type of sex determination, the Y-chromosome seems to be inactive in aE tissues. The X-chromosome is inactivated during the last spermatogonial division and remains so throughout spermatogenesis. The X-chromosome of Pyrrhocoris, which is of the XX/XO type of sex determination is inactive in the same stages as that of Oncopeltus and during an additional phase in early oogenesis. X inactivation in spermatogenesis is interpreted as a form of gross regulation of gene activity on the chromosomal level.