Localization of Genes Involved in DNA Repair on Human Chromosomes by Using Cell Fusion

The use of somatic cell hybrids in human gene mapping is based on the fact that human chromosomes are preferentially lost in proliferating hybrids formed between human cells and tissue culture adapted rodent cells. When it is possible to discriminate between homologous human and rodent gene products, correlation of the expression of the human phenotype in the hybrids with their human chromosome pattern allows the assignment of genes to a specific chromosome. In the case of DNA repair, the gene products are unknown and the analysis has to rely on less specific characteristics and differences between the human and rodent repair systems, like the level of repair DNA synthesis. We report differences in repair systems between normal human and Chinese hamster cells and analysis of the repair capacity of proliferating human-Chinese hamster cells.