Evidence for two distinct c-src loci on human chromosomes 1 and 20

A number of proto-oncogenes have recently been localized to the chromosomal segments that are the breakpoints in the specific rearrangements noted in human malignant diseases. Moreover, rearranged forms of several proto-oncogenes have been identified in malignant cells; in several instances, the proto-oncogene has undergone an alteration as a result of a nonrandom chromosomal rearrangement. One proto-oncogene that has yet to be associated with human neoplastic disease is c-src, the cellular homologue of the transforming sequence of Rous sarcoma virus (RSV). By somatic cell hybridization, c-src has been mapped to chromosome 20, but its precise location was not determined. We have now mapped this gene by using in situ hybridization of the cloned human c-src probe to human mitotic chromosomes. We report here that the human genome contains two loci with strong homology to the coding regions of this oncogene, at 1p34-p36 and 20q12-q13. It is noteworthy that these chromosomal regions are frequently involved in the structural rearrangements observed in haematological malignant diseases.