Studies in Human Inheritance. V. Multiple Allelomorphism as Opposed to Linkage in Blood Group Heredity

Abstract

THIE inheritance of the hnman blood groups has been shown to be dependent upon a set of triple allelomorphs (Bernstein, 1925, Snyder, 1926, 1929, et al.). Based on this interpretation, laws relating to legal and clinical medicine, and to anthropology, have been formulated (Snyder, 1927, 1929, 1930). The evidence for the triple allelomorph hypothesis was considered adequate, and the question of the mode of inheritance of the blood groups was, I thought, settled. Former suggestions of hyTpotlheses, involving, respectively, two pairs of independent factors and two pairs of completely linked factors, had been shown to be untenable. In 1928, however, a short note appeared by K. H. Bauer, suggesting the assumption of two pairs of partially linked factors, instead of triple allelomorphs, as the basis for the inheritance of the blood groups. This hypothesis was said by its proposer to explain thle exceptions which had been observed by various workers in the offspring of certain crosses. Bauer assumed 11 per cent. cross-over between the two linked factors. This hypothesis, however, is genetically as untenable as the old hypothesis of independent assortment. In my monograph on the blood groups (Snyder, 1929), I mentioned briefly the linkage hypothesis, stating that it could not adequately explain the observed facts, and giving concise specific reasons for my statement. In spite of this, however, in two text-books which have just appeared, Bauer's hypothesis of linked factors is accepted. 1 Contribution from the Department of Zoology and Enitomology of the Ohio State University, No. 105.