Isolation and chromosomal localiza from a human genomic library (recombinant DNA/human chromosomes/synteny analysis/hybrid ce

Recombinant bacteriophage A from a human ge- nomic library were screened to identify human DNA inserts hav- ing only unique sequences. Unique human inserts were found in about 1% of the phage screened. One recombinant phage, P3-2, was studied in detail. It contains a human insert of 14.7 kilobases with four internal EcoRI cleavage sites. A restriction map was con- structed for EcoRI and BamHI sites. Hybridization of the 32P-la- beled P3-2 probe to a Southern blot of EcoRI-digested total human DNA yielded distinct bands at positions corresponding to the hu- man insert fragments contained in P3-2. By using a series of hu- man-Chinese hamster somatic cell hybrids containing unique combinations of human chromosomes, the human DNA segment in phage P3-2 was assigned to human chromosome. 22 by blot hy- bridization and synteny analysis. In addition, another human DNA segment, 11.4 kilobases, in phage P3-10 was assigned to human chromosome 10 by similar procedures. With this approach, more unique DNA sequences can be isolated, assigned to specific human chromosomes, and used as genetic markers for gene mapping and linkage, polymorphism, and other genetic studies in the human genome.