Figure 2:

A pedigree of a quartet family is shown with father, mother and two children as indicated with thin solid lines. A set of parental haplotypes is built from Trio1 with father, mother and child1, as shown with a black bold triangle. A second set of parental haplotypes is built independently from Trio2 with father, mother and child2, as shown with a gray bold dotted triangle. The resulting two sets of parental haplotypes are compared for validation; both sets of parental haplotypes are identical if no meiotic crossover event occurred in either of the children. This validation facilitates identification of not only a recombination event but also inconsistent HLA allele segregation within the same haplotype due to HLA typing errors.