Characterization of a Mus spretus YAC that maps to the pseudoautosomal region

A library, containing M. spretus DNA in a half-YAC vector, was made and screened for clones hybridizing with an oligomer of the telomere hexamer TTAGGG. FISH to metaphase spreads of spleen cells showed hybridization of clone YTY3 to the distal ends of both X and Y chromosomes, consistent with localization to the pseudoautosomal region (PAR). Recombinational mapping in the BXD RI strains and an interspecies backcross, using a plasmid subclone and PCR primers from YTY3, showed linkage to distal Chr X. The restriction map of the YAC contains three NotI sites. Sequences similar to Mov15 lie close to the vector end of the clone, while the other end contains a telomere array that appears to be interstitial within the PAR, suggesting that the insert represents a proximal portion of the PAR. Sequences homologous to the clone are also present at subtelomeric regions of autosomes 4, 9, and 13.