Two nonallelic tRNA(i)(Met) genes are located in the p23→q12 region of human chromosome 6

Two nonallelic human tRNA(i)(Met) genes were assigned to chromosome 6 by filter hybridization of DNA from human-rodent somatic cell hybrids by using probes containing unique sequences from the regions flanking each tRNA(i)(Met) gene. These unique sequence probes thus allowed each tRNA(i)(Met) gene to be analyzed individually in cell hybrids. Both tRna(i)(Met) genes segregated in the hybrid cells with the chromosome 6 enzyme markers, soluble malic enzyme and the mitochondrial form of superoxide dismutase, and also with a karyotypically normal chromosome 6. By using hybrid clones containing translocations that divide chromosome 6 into five segments, both tRNA(i)(Met) genes were assigned to the p23→q12 region. These results raise the possibility that other tRNA(i)(Met) genes may be syntenic with the two described in this study and illustrate the utility of using unique lanking sequences to identify members of a multigene family.