Figure 2.

Segregation of sst1 alleles in the progeny of recombinant males. Males that carried recombinations within the sst1-containing segment of chromosome 1 were identified by genotyping with microsatellite markers using DNA obtained from tail biopsies. Recombinant males were crossed with C3H females, and their progeny was genotyped and tested for susceptibility to i.v. infection with M. tuberculosis. Each column of boxes represents a genotypic class. The number of recombinant males per each genotypic class is denoted by the digit under each column. Each box represents the genotype for loci corresponding to chromosome 1 map on the left. Solid boxes represent homozygotes for B6 alleles, striped boxes are heterozygotes, and open boxes are homozygotes for the C3H allele. The survival times of the progeny heterozygous or homozygous for each marker was compared by using Student's t test. Significant differences between those groups (P < 0.0001) indicated heterozygosity of the recombinant male for the sst1-resistant allele. The sst1 genotypes inferred by this method are at the top of the figure. The two horizontal lines drawn between D1Mit334 and D1Mit45 designate the location of the sst1-containing segment.