Quantitative detection of single-copy genes in nanogram samples of human genomic DNA.

We have developed methods for Southern hybridization analysis of single-copy genes in as little as 10 ng of mammalian DNA electrophoresed under either neutral or alkaline conditions. The signal on the radiogram is proportional to the quantity of DNA. These methods permit Southern hybridization analysis of DNA from about 2 x 10(3) cultured human cells. The use of minimal cell numbers greatly reduces the costs of culturing cells for hybridization analysis and makes feasible analysis of DNA from tissues or cell types available only in limited quantities.