showed that the histone macroH2A1.2 relocates to these structures after they are formed.
These structures are notably absent in dogs and cats with the Pelger-Hu? anomaly, and they are absent in flies and C. elegans because, in those organisms, their major function is performed by the Sxl and sdc-2 proteins, respectively. Boggs et al. hypothesized that these structures may be characterized by hypoacetylation of core histones, and Mermoud et al. showed that the histone macroH2A1.2 relocates to these structures after they are formed. Their formation is opposed by the gene TSIX, which inhibits the production of siRNA by the gene XIST. They are formed by lyonization, named after Mary Lyon, who hypothesized that they are responsible for dosage compensation. These structures are absent in Turner's syndrome, while multiple ones of them occur in Kleinfelter's syndrome. For 10 points, name these inactivated X chromosomes.
These structures are notably absent in dogs and cats with the Pelger-Hu?
Barr bodies [accept early inactivated X chromosomes]