Novel Approach Identifies SNPs in SLC2A10 and KCNK9 with Evidence for Parent-of-Origin Effect on Body Mass Index
Figure 1
Top panel illustrates the phenotype distributions in the four genotype groups that would be observed if the parent-of-origin of the alleles were known. Bottom panel shows how these distributions change if the parent-of-origin is unobserved. The resulting heterozygous group will have increased variance due to its heterogeneity. This example describes a scenario we observe for the two replicated hits, namely that the paternal- and maternal effects are of the same size, but opposite in direction (). Therefore the average phenotype in the B/B group is the same as in the A/A group, as the paternal and maternal B allele effects cancel each other out. In the A/B group there are two subpopulations: the A-pat/B-mat group with phenotypic mean of
and the A-mat/B-pat group with
mean. Thus, the two subpopulations combined also have zero mean, but increased variance.