Plasmid Profile Typing and Plasmid Fingerprinting

Plasmids are extra-chromosomal molecules of deoxyribonucleic acid (DNA) capable of autonomous replication. Such molecules have been identified in many bacterial genera and usually exist as covalently closed circular (CCC) molecules. Plasmids range in size from less than one megaDalton (MDa) to several hundred MDa. One megaDalton of double-stranded DNA is equivalent to 1500 bp or 1.5 kilobases (kb, see Note 1 ).