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Table 1 IBD configurations for pairs of individuals

From: Identity by descent and association analysis of dichotomous traits based on large pedigrees

State

Description

S 1

BB/BB; IBD = 1

S 2

BB/BB; IBD = 0.5

S 3

BB/BB; IBD = 0

S 4

BB/AB; IBD = 0.5

S 5

BB/AB; IBD = 0

S 6

BB/AA; IBD = 0

S 7

AB/AB; IBD = 1

S 8

AB/AB; IBD = 0.5

S 9

AB/AB; IBD = 0

S 10

AB/AA; IBD = 0.5

S 11

AB/AA; IBD = 0

S 12

AA/AA; IBD = 1

S 13

AA/AA; IBD = 0.5

S 14

AA/AA; IBD = 0

  1. Consider a SNP marker with two alleles, A and B. Between two individuals, if both alleles are identical by descent (IBD), then the IBD score is 1; if one allele is IBD, then the IBD score is 0.5; and if no allele is IBD, the IBD score is 0. For an arbitrary pair of samples within the same family k, there are 14 combinations of their IBD scores and genotypes, shown here as S1 to S14.