Gene clusters in the blood group system B of cattle

In this report the linear order of genetic determinants for the blood group system B of cattle has been worked out in more detail. Two groups of antigenic specificities--inclusion groups--showing serologic relationship are described. Recombination frequencies do suggest that these specificities are controlled by two clusters of genetic determinants. The structures of these inclusion groups and clusters are compared with those of antigenic complexes in other species, especially in mice. Several similarities and also dissimilarities between the blood group system B of cattle and the H-2 system in mice are described.