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Thread: DNA Extraction

  1. #1 DNA Extraction 
    Forum Freshman
    Join Date
    Sep 2006
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    32
    OK...I'm a little bit unsure of my anwsers in regards to extracting DNA from peas so I was hoping if anyone could confirm them for me. I looked up a site that had remotely the same procedure if it helps http://learn.genetics.utah.edu/units...es/extraction/ The anwsers are in regards to the procedure to show the importance of each step in order to extract DNA...

    What is found in the meat tenderizer that is needed for DNA to be extracted?
    - The meat tenderizer acts as an enzyme such as Bromelain and Papain, which are proteases to cut away proteins (histones) from the DNA allowing for it to unravel. This reactant is important because... (I'm a little stuck on this... I know what histones are, but cannot seem to find anything on why they must be removed in order to unravel the DNA...ideas?)

    Liquid detergent is an emulsfying agent, why is it needed?
    - While the blender separates the pea cells, there still remains the issue of isolating the DNA for extraction, which is achieved by utilizing an emulsifying agent (detergent) to destroy both the cell membrane and the nuclear membrane. Since, an emulsifying agent is amphiphilic (like likes like) and the two membranes consist of lipids and proteins, the detergent will combine with the two in order to destroy the membranes allowing DNA to be extracted.

    Why does the DNA collect in the alcohol layer?
    - Since alcohol is less dense than water, it stays afloat on top of water whereas the cell residue settles at the bottom. DNA precipitates when in the presence of alcohol, which means that it is insoluble in alcohol causing for the collection of DNA in the alcohol layer.

    I know I'm asking for a lot, but even if anyone could just review one of my anwsers it would be greatly appreciated![/i]


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  3. #2  
    Forum Sophomore
    Join Date
    Sep 2006
    Location
    Edmonton, AB, Canada
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    I would simply use an Phenol/Chloroform extraction (even though they are smelly).

    You would want to add a protease of some sort to get rid of DNAses (which would otherwise degrade your DNA).


    It is not so much that I have confidence in scientists being right, but that I have so much in nonscientists being wrong. --- Isaac Asimov
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