Exclusion of Sox9 as a candidate for the mouse mutant tail-short.

The Sry-related gene Sox9 has been proposed as the gene responsible for the mouse skeletal mutant Tail-short (Ts), on the basis of its expression in skeletogenic mesenchymal condensations in the mouse embryo and its chromosomal location in the region of Ts on distal Chromosome (Chr) 11. We present here detailed mapping of Ts locus relative to the Sox9, using an intersubspecific cross. Among 521 backcross progeny, 16 recombinants were detected between Sox9 and Ts, suggesting a separation of 3.5 +/- 0.01 cM, and excluding Sox9 as a candidate for Ts. A further nine recombinants were detected between Ts and the polycomb-like gene M33, suggesting that these loci are separated by 1.8 +/- 0.011 cM. Six microsatellite markers were co-localized to the Ts locus, providing reagents for positional cloning of Ts.