11:115:301 Lecture Notes - Lecture 22: Restriction Enzyme, Recombinant Dna, Southern Blot
22 Sep 2019
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Document Summary
Restriction enzymes cut dna at specific sequences. Digest dna so it becomes more manageable to work with. Most useful recombination enzyme recognize 6 bases. Restriction endonuclease can cut in many ways within 6 base sequence. Recognize + cut both strands of duplex dna at specific sequences. 5"-3" sequence is the same on top + bottom strand. Biological function = primitive immune system against invading viruses. Bacteria protects own dna by methylation of the restriction sequences in its genome. Names of restriction enzymes derived from their host bacteria. Cleavages blunt ends (haeiii) or overlapping ends (bamhi) Easier to ligate to other dna molecules. These enzymes are preferred when making dna vectors. Large fragments travel slower (closer to top) Small fragments travel faster (closer to bottom) Small fragments don"t binds to etbr as well electrophoresed on a gel. Dna from 2 viruses digested by 4 different restriction enzymes . Comparisons of dna fragments used to detect mutations or identify individuals (forensic analysis)
