Correlation between sexual phenotype and X-chromosome inactivation pattern in the X*XY wood lemming.

Replication patterns of the X chromosomes were studied in X*XY wood lemmings with male and female phenotypes. The wild-type X was late replicating (ie, inactivated) in all cells of the X*XY female, whereas the mutated X* was late replicating in all cells of the X*XY male. These findings are compared with those obtained in sex-reversed (Sxr) mice.