A REVISED MAP POSITION FOR THE HA-RAS GENE ON MOUSE CHROMOSOME-7 - IMPLICATIONS FOR ANALYSIS OF GENETIC ALTERATIONS IN RODENT TUMORS

The mouse Ha-ras gene has previously been mapped to the central region of chromosome 7, 31 cM from the centromere, using an interspecific Mu s musculus/Mus spretus backcross (Saunders AM, Seldin MF, Genomics 8:5 25-535, 1990). However, analysis of mitotic recombinations in mouse sk in tumors from intraspecific F1 hybrid mice suggested a more distal lo cation for the Ha-ras gene on chromosome 7 (Bremner R, Balmain A, Cell 61:407-417, 1990). in the study reported here, we demonstrated, by an alysis of Ha-ras gene mutations in skin tumors from interspecific M. s pretus/M. musculus F1 hybrids, the existence only in M. spretus of a p seudogene or other Ha-ras-related sequence that is probably the sequen ce originally mapped by Saunders and Seldin. The functional Ha-ras gen e maps to the distal region of chromosome 7, and it is this sequence t hat acquires mutations in chemically induced tumors.