Studies in Isohemagglutination

Abstract

Summary and Conclusions Formulae were derived for calculating the chances of proving non-paternity by means of characters whose heredity involves a single pair of allelomorphic genes, several independent pairs of allelomorphic genes, and multiple allelomorphic genes. These formulae may be applied not only to the inheritance of agglutinogens but also to the inheritance of any physiological trait whose heredity is defined sharply enough to allow of medicolegal application. All that is necessary is to determine the mechanism involved and then apply the proper formulae. The maximum chances of proving non-paternity was calculated in each case. As far as the Landsteiner blood groups are concerned, there can be no question that the von Dungern and Hirszfeld theory is wrong and that the Bernstein theory is correct or very nearly so. Nevertheless, von Dungern and Hirszfeld will always be remembered as the first to point out that the agglutinogens A and B are inherited like mendelian dominants. The frequencies of the blood groups as found by the authors were: Ō = 36.36 per cent, Ā = 40.48 per cent, B̄ = 17.09 per cent and AĀB̄ = 6.07 per cent. With this distribution of the groups, according to the Bernstein theory, non-paternity can be proved in 18.05 per cent of the cases in which the putative father is not the true father. If one were to be conservative and did not consider as illegitimate cases in which the putative father belongs to group AB and the child to group O, or cases in which the putative father belongs to group O, and the child to group AB, the chances of proving non-paternity would be reduced to 14.75 per cent. The results obtained by means of our formulae were compared with the results that Hooker and Boyd obtained. Formulae for the chances of proving non-paternity by means of the new agglutinogens M and N of Landsteiner and Levine were also derived. Landsteiner and Levine have discussed two theories of heredity for these agglutinogens. The theory of a single pair of allelomorphic genes fits the facts best at present. According to this theory, the average chances of proving non-paternity by means of M and N would be 18.75 per cent, when the frequencies of the groups are: (M+N-) = 26.81 per cent, (M+N+) = 45.65 per cent and (M-N+) = 27.54 per cent. Should it be confirmed that there are exceptions to this theory, some modification of the concept would be necessary. When one does not consider as illegitimacies (M+N -) children with (M-N+) fathers or (M-N+) children with (M+N-) fathers, the chances of proving non-paternity by means of M and N become 6.25 per cent.