Using somatic cell hybrids between TK-deficient mouse cells and white blood cells derived from a patient with a translocation of the region p21→pter of chromosome 17, we have assigned the gene for human GLO to region p21→pter of chromosome 6. Since the HLA region is only 10 cM distant from GLO, these results also confirm that the HLA region is located on the short arm of human chromosome 6.

We have studied the expression of mouse galactokinase in human-mouse somatic cell hybrids segregating mouse chromosomes. Since concordant segregation of the expression of mouse galactokinase and the presence of mouse chromosome 11 were observed in the hybrid clones, we conclude that the gene for mouse galactokinase is located on mouse chromosome 11. We have also investigated the expression of mouse galactokinase in somatic cell hybrids between thymidine kinase-deficient Chinese hamster cells and mouse peritoneal macrophages. The results of this study indicate that the expression of mouse galactokinase and thymidine kinase segregates concordantly, and, therefore, we infer that the gene for mouse thymidine kinase is also located on mouse chromosome 11.