Figure 2.

Visualization of founder risk haplotypes carrying DRB1*1501 (DR2). Shown are all founder haplotypes carrying allele 6 at marker D6S2446 (D6S2446-6). The consensus ancestral haplotype containing D6S2446-6 was determined, and individual alleles were color-coded: marker alleles identical to consensus are shown in maroon, alleles different from consensus are shown in gold, and missing data or alleles with ambiguous phase are shown in gray. After sorting by length, groups of founder haplotypes were tested by TDT, with the numbers shown referring to the ratio of T:NT haplotypes. Blue boxes indicate significant transmission distortion (P<.05) for the larger groups; white boxes indicate nonsignificant TDTs. A, Founder haplotypes (N=176) were sorted by telomeric (left) length, and TDTs were performed. B, Founder haplotypes (N=176) were sorted, first by centromeric (right), and then by telomeric (left) length, to define the centromeric “breakpoint” by TDT. C, Founder haplotypes (N=155) carrying the TNF-α allele found on the DRB1*1501 extended haplotype were sorted on the basis of centromeric (right) length. Only those haplotypes extending to DRB1/DQB1 were significant by TDT. At the bottom of panel C are four “double recombinant” haplotypes, showing consensus markers for the TNF and class II regions but showing nonconsensus in-between; T:NT ratio is 3:1. Asterisks (*) represent the approximate boundaries of the haplotype length showing convincing evidence for transmission distortion. Haplotype groupings that failed to show significant transmission disequilibrium (white boxes) did not contain DRB1*1501, despite carrying D6S2446-6.