DNA Fingerprinting

Introduction to DNA Fingerprinting Technicians in forensic labs are often asked to do DNA profiling or “fingerprinting” RFLP analysis provides a unique banding pattern based on the restriction sites present in an individual’s DNA sequence

Restriction Enzymes Discovered in bacteria Enzymes that cut DNA in a specific place Along both strands Enzymes scan DNA looking for a particular sequence to cut (usually 6 or so nucleotides) Bacteria use restriction enzymes to protect themselves against viral DNA in a process called restriction

Restriction Enzymes Restriction Enzymes cut DNA at recognition sites, and leave “sticky ends”

Restriction Fragment Length Polymorphisms (RFLPs) Fragments result from treating a DNA sample with restriction enzymes The fragments can be separated based on their size using Gel Electrophoresis A current forces DNA towards positive pole (nucleic acids have negative charge) Each person has similarities and differences in DNA sequences

Forensics There has been a crime locally and evidence has been collected from the scene. (CS) DNA has been collected from several suspects for analysis