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Alternative methods of dna extraction, purification, and its advantages.
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So there are several different ways to extract dna.
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So one of the ways to extract dna is called phenol chloroform extraction.
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So phenol chloroform, they are organic chemicals.
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So they basically use phenol and chloroform to separate dna from protein and other cellular components.
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And chloroform and phenol is going to remove the protein and remain in organic phase.
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And the dna will actually go into the aqueous phase.
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So the idea is that the cells are being broken to, this is the nucleus.
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And so the cell will be broken to release the dna a lot of times by grounding by a mortar and pestle.
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And then the cell extractions are being released to treat with phenol and chloro extraction.
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So then after going through a centrifugation, the phenol chloroform extraction is able to separate the mixture into two layers.
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So one is called the, what we call the organic phase.
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The organic phase will actually have the protein step by into the dna and other impurities.
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And then you have another layer, this is the aqueous.
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The aqueous phase will contain the dna.
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So by extract the aqueous phase, you're able to separate dna from the protein.
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So what is the advantage of this method? and so phenol chloroform is a very effective way to remove protein and other contaminants.
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So this is a lot of time used in plant dna extraction because a lot of plants, they have a large amount of protein and other contaminants such as polysaccharide.
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So this is a very effective way to extract dna from the plant cells, which is harder to extract and also contain large amount of protein and contaminants such as polyacrylamide.
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So very effective for removing proteins and polysaccharide.
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So this is usually used against for plants cell dna extraction.
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And usually it is also used for large scale dna extraction.
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So that means you have a huge amount of sample and you'll produce a lot of dna at the end, high yield.
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So this is the advantage of the dna extraction by use phenol chloroform extraction.
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Another method, what we called is the spin column dna purification.
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So obviously, you know that in this case, we do not use the organic chemical compounds such as phenol and chloroform.
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Instead, we use a spin column.
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The spin column is silicon based.
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So the idea is that a silicon membrane based column will bind dna selectively so that when the dna goes through the column, the dna is going to bind to the column while the contaminants or other impurity is going to flow through.
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And so at the end, the dna will be eluded to a clean tube.
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So let me draw what happened.
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So usually what happened is this is used for dna extraction in bacteria.
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So you will break again the cell and break the membrane and release the dna.
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And then you're going to go through a spin column.
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Let's say the spin column is silicon based.
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So that the mixture is going to go through the column.
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So while other stuff flow through has contaminants wash out and the dna is going to stick to the column.
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So the green stuff is dna is going to bind to the column and other contaminants are being washed.
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And then eventually you'll have elution buffer to elute.
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So you'll collect the dna in a new tube.
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And this step is called elution.
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The buffer is going to add into the column and then the buffer will bring down the dna.
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So the clean dna will be eluted.
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So the advantage is that because it doesn't use the phenyl chloroform, which are toxic organic compounds, they are usually a lot easier, rapid and straightforward without the harmful chemicals.
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So there's no toxic chemicals such as phenyl or chloroform.
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Second, rapid.
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So the spin column method is a lot faster than the phenyl chloroform.
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And it's also very straightforward.
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So it doesn't have the multiple step required for the phenyl chloroform method.
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Also, it is able to produce a large amount of dna and with high purity.
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All right.
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So now let's take a look at the last one.
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The last one, what we call is magnetic beads extraction.
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So according to the name, you can probably guess what it is.
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So the beads, the magnetic beads are coat with substances and they're mixed with dna cell lysate.
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So that dna is going to actually bind to the beads just like what we just talked about...