The use of biotinylated DNA probes for detecting single copy human restriction fragment length polymorphisms separated by electrophoresis

Human genomic DNA probes labeled by nick translation with biotin 11‐UTP were successfully used to identify single copy restriction fragment length polymorphisms following electrophoresis and Southern blotting onto nylon membranes. Two human probes found on chromosome 21 were used, each of which demonstrated polymorphisms using two separate restriction endonucleases. Compared to isotopic labeling of probes the biotin labels are safer, faster and more economical. The detection method of streptavidin‐biotin‐alkaline phosphatase permitted phenotyping in a matter of hours after hybridization of the probe to the human DNA fragments.