Physical maps of the jal region on mouse Chr 2. (a) Molecular markers and genes on mouse Chr 2 that are linked with jal. Segregation data from the 374-member backcross panel shown in Figure 3 placed jal between microsatellite markers D2Mit359 and D2Mit80 (shown in blue), an interval that also includes Il2ra (shown in gray). Single-nucleotide polymorphisms (SNP1-4, see Additional file 2 and Additional file 3) were used to more precisely locate crossovers among the 41 mice recombinant in this interval. The number of crossovers located between the various pairs of adjacent markers are shown on the chromosome map, which is drawn to the 5 Mb scale shown. Seven recombinants located jal between SNP1 and SNP2 (shown in red). The region between SNP1 and SNP2 is expanded below the chromosome map (drawn to the 0.1 MB scale bar shown), to show the locations of the 10 candidate genes (represented by orange boxes) that populate this span. Of these ten genes, only one, Gata3 (shown in yellow), is known to be expressed in skin. (b) The Gata3 gene is expanded to show the arrangement of exons, where taller boxes are coding regions and shorter boxes are the 5′ or 3′ untranslated regions. Gata3 is transcribed from the reverse strand, but is drawn here so that the six exons are shown in ascending numerical order. The length of each exon (in bp) is shown below the corresponding box. The portions of exons shaded green have been sequenced in C3H/HeJ and C3H/HeJ-jal/J DNA, but no differences were found.