**3.4 Haplotype analysis of sensitive and resistant strains**

The CBA/J strain is a cousin to C3H. Like its relative, CBA/J is highly susceptible to liver tumorigenesis, and the dominant modifier mapped in crosses between CBA/J and B6 maps to distal Chromosome 1 (Bilger et al., 2004). Because these strains are likely to share a susceptibility allele, we generated a haplotype map of the minimal *Hcs7* region in CBA using SNPs obtained through the Imputed SNP Database (Szatkiewicz et al., 2008). Only SNPs that could be determined with greater than 80% confidence were included (Figure 4). This map suggests that CBA is highly related to the C3H strain through most of the *Hcs7* region, confirming the likelihood that these two sensitive strains share one or more susceptibility alleles.

Fig. 4. Haplotype maps for the *Hcs7* interval.

Haplotypes were determined for each gene and intergenic region. B6 haplotypes are shown as tics above the bar. C3H haplotypes are shown as tics below the bar. Haplotypes unique to CBA are shown as grey tics centered on the bar, while haplotypes unique to BR are shown as outlined tics centered on the bar. The starting position of each gene is shown as a tic above the position axis.
