Restriction Enzymes and DNA Fingerprinting

Molecular Scissors for Cutting DNA Precisely Its because of these biological catalysts that genetic engineering is possible Restriction enzymes can also be called Endonucleases

Types of Restriction Enzymes Type I Binds to the recognition site and then cut randomly somewhere along the length of the molecule Type II Binds to the recognition site and then cleaves the molecule by clipping the DNA backbones particular DNA molecule with a particular restriction enzyme will always produce the same set of DNA fragment Type III and Type IV

Types of Cuts Blunt end Cutters Sticky-end Over- hangers

Uses Restriction enzymes can be used in processes such as… Southern Blotting Cloning Verification And Forensic DNA Fingerprinting

Southern Blotting 1 st step of Southern Blotting is digestion of DNA where the restriction enzymes come in Hind III was the restriction enzyme used to cut up the DNA Hind III comes from Haemophilus influenzae Rd

Genomic DNA digestion and Southern Blots UC C UC C UC C

Cloning Verification Eco RI or Escherichia coli RY 13 was used

Forensic DNA Fingerprinting Was first described in 1985 by geneticist Alec Jeffreys who discovered That some sections of DNA contain DNA sequences that were repeated over and over again The number of repeated sequences vary from individual to individual Dr. Jeffreys also created the technique known as restriction fragment length polymorphism (RFLP) to examine the length variation of these DNA repeat sequences

VNTRs and STRs VNTRs (variable number of tandem repeats) and STRs (short tandem repeats) are DNA repeating sequences VNTRs are also known as minisatellites which range from bases in length STRs are also known as microsatellites which range from 2-6 bases

STRs and Forensic Fingerprinting The small size of STRs are better suited for use in forensic applications where degraded DNA is common In core STR loci were chosen to be the basis of CODIS (Combined DNA Index System) CSF1PO, FGA,TH01, TPOX, VWA, D3S1358, D8S1179, D13S317, D16S539, D18S51, AND D21S11 PE Applied Biosystems and Promega Corp. produce STR kits