Heterozygosity reduction in children whose parents are closely related

In this study, the impact of consanguineous marriage and inbreeding on heterozygosity was evaluated by comparing levels of heterozygosity in children of closely related parents with those of unrelated parents. Compared to the average expected heterozygosity, the average observed heterozygosity was lower in the children with first-cousin parents. This was not the case in the children with unrelated parents, where an increase in the average observed heterozygosity was noted. Differences in the average heterozygosity between parents-children also observed between related and unrelated parents. First-cousin parents had higher average heterozygosity than the children compared to the unrelated parents where the average heterozygosity was lower than the children. Further investigation with bigger sample size and different populations will provide better understanding, however this study showed that a careful approach should be taken when dealing with parentage testing involving closely related parents.