Method of detecting foreign DNA integrated in eukaryotic chromosomes

摘要

Methods of detecting the presence of a plasmid DNA sequence integrated in a chromosomal DNA molecule of a eukaryotic cell in a sample that contains chromosomal DNA molecules of eukaryotic cells and free plasmid DNA molecules are disclosed. According to the invention, chromosomal DNA of eukaryotic cells which are free of deoxyadenosine methyltransferase, and free plasmid DNA molecules which are produced in cells that contain deoxyadenosine methyltransferase and which have a DpnI site, are digested with one or more restriction enzymes that cleave plasmid DNA sequences integrated in the chromosomal DNA and plasmid DNA molecules to produce DNA digestion segments that are then fractionated to produce a plurality of fractions. The DNA digestion segments in each fraction is digested with DpnI and plasmid DNA sequences are amplified using sets of primers that flank a DpnI site in the plasmid DNA sequence. The presence of amplified fragments indicates the presence of a plasmid DNA sequence integrated into the chromosomal DNA.