Molecular Genetics of <i>de^H</i> and <i>Tbx15</i>

<div><p>(A) Genetic and physical map, as described in the text. Markers M1 to M3 are SSCP markers generated from a BAC contig of the region; marker M4 is STS 16.MMHAP32FLF1 and was also used as an SSCP marker. M2 and M3, which flank the <i>Tbx15</i> and <i>M6pr-ps</i> on the UCSC genome browser map and lie 634 kb apart, were nonrecombinant with <i>de^H</i> in 2340 meioses.</p> <p>(B) The <i>de^H</i> mutation is a deletion that starts in <i>Tbx15</i> intron 1 and ends in the <i>M6pr-ps</i>.</p> <p>(C) Sequence of deletion breakpoints.</p> <p>(D) Diagram of <i>Tbx15^LacZ</i> allele constructed by gene targeting. As described in the text, this allele is predicted to give rise to a protein truncated after approximately 154 codons and is lacking critical residues of the T box. Heterozygotes for the targeted allele exhibit normal size, morphology, and hair-color patterns, but homozygotes and <i>Tbx15^LacZ</i>/<i>de^H</i> compound heterozygotes are identical to <i>de^H</i> homozygotes.</p>