Figure 2.
Parent transmission disequilibrium testing in the chromosome 21 region. Single nucleotide polymorphism (SNP) genotypes were tested for association with the cold sore phenotype (frequently affected vs unaffected) among 25 family trios (50 parents + 25 offspring) from the Utah Genetic Reference project. White circles denote the chromosomal locations (bp × 106) of the tested SNPs plotted against the computed χ2. The black bars show the approximate gene locations. Arrows indicate the direction of transcription of the gene. The dashed line across the figure represents P ≤ .05 (χ2 ≈ 3.8).