Docstoc

Restriction Enzymes and Gel Electrophoresis

Document Sample
Restriction Enzymes and Gel Electrophoresis Powered By Docstoc
					Restriction Enzymes and
     Gel Electrophoresis
               Genetics 335
Step 1: Restriction enzymes/endonucleases
   Enzymes that cut DNA into fragments of different sizes

   Cleave DNA at specific phosphodiester bonds

   Named after bacterial strains
       E.g., BamHI, EcoRI, HAEIII, HindII, MstII


   Can cleave straight (flush) or staggered
       Blunt or sticky ends
Why cut up DNA?
   If different alleles can be cut up and identified (using GE),
    we can identify unknown persons (e.g., criminals,
    biological relatives), and document unknown genotypes
    (e.g., Huntington’s Disease)

   http://www.youtube.com/watch?v=KVnFBCzg8Ms
Gel Electrophoresis
   You have a vial of undescribed DNA fragments—now
    what?
   Samples pipetted into wells on one end of a gel (e.g.,
    agarose)
   Electricity is added to the gel
   DNA fragments move through the gel at different rates,
    away from the negative and toward the positive end
       Smaller fragments move easier and further from well, larger
        fragments more cumbersome and move shorter distances
        from well
   The resulting “fingerprint” of fragments can be matched
    to a known sample or investigated for specific alleles
A   B   C   D   E   F   G
Videos
   http://www.sumanasinc.com/webcontent/animations/cont
    ent/gelelectrophoresis.html

   http://www.youtube.com/watch?v=lM8npqHw-mk
Review
   Restriction enzymes cut up DNA into pieces unique to
    your DNA
       DNA pieces are a function of your genetics and the restriction
        enzyme used
   DNA fragment soup placed in Gel well and distributes
    based on fragment/sequence length
   Resulting gel is unique—like a fingerprint

				
DOCUMENT INFO
Shared By:
Categories:
Tags:
Stats:
views:22
posted:4/6/2012
language:English
pages:8