Assignment of a third purine biosynthetic gene (glycinamide ribonucleotide transformylase) to human chromosome 21

Using a series of human-hamster hybrid cell lines, a gene coding for glycinamide ribonucleotide transformylase was mapped to human chromosome 21. The availability of hybrids containing only portions of chromosome 21 allowed the gene to be assigned to the region between the q11.2 and the q22.2 bands, inclusive. Differentiation of human and hamster glycinamide ribonucleotide tranformylase was accomplished via an immunoprecipitation assay that employed a polyclonal antibody raised against the human enzyme.