Patchy fur,a Mouse Coat Mutation Associated with X–Y Nondisjunction, Maps to the Pseudoautosomal Boundary Region

Patchy furis a semidominant X-linked mutation in the mouse, resulting in a sparse coat. ThePafmutation also alters the normal segregation of the X and the Y chromosomes during male meiosis by causing nondisjunction at anaphase I. Analysis of 1139 female meioses from an intersubspecific backcross using 15 PCR-based markers localizesPafto an 0.2-cM interval that includes the pseudoautosomal boundary. The meiotic nondisjunction phenotype may result from a chromosomal rearrangement that includes pseudoautosomal sequences and affects XY pairing.