Chromosome assignment of the human gene for galactose-1-phosphate uridyltransferase

Somatic cell hybrids formed between galactose-negative mutant Chinese hamster cells and human lymphocytes were selected in galactose medium and analyzed for the concurrent presence of specific human chromosome(s) and human galactose-1-phosphate uridyltransferase. In one of the hybrid clones only a single human chromosome, A2, was consistently present when the hybrid cells were maintained in the selective medium, suggesting that the location of the structural gene for galactose-1-phosphate uridyltransferase is on this chromosome. Among subclones derived from this cell hybrid in the absence of selection, a complete concordance was demonstrated between the ability or inability to utilize galactose and the concomitant presence or absence of the human transferase and the A2 chromosome.