Quote:
Originally Posted by merleniau
The pattern you'll get depends on what enzyme you use to cut the DNA. I would assume that you can get different restriction enzymes to create different patterns.
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My first thought was exactly 'I wonder what restriction enzymes they use?'
Quote:
Originally Posted by DNA 11
Labwork
01.
We receive your DNA sample
When you mail your sample to our secure laboratory, it arrives with a barcode that we scan. Your identity is secure: the tracking number from the barcode is the only reference the lab works with. (No one at the lab will know who you are.) As soon as the barcode has been scanned, an automatic email is sent to you indicating that we have received your DNA sample.
02.
We begin the labwork
Now we get down to work. We extract your DNA from the FTA card and suspend the sample in a liquid buffer. We then put your DNA through a process that searches and isolates unique sequences found in your genome. (Everyone has a different number of these sequences found at different locations.) We put your DNA through a process called polymerase chain reaction (PCR) to replicate your unique sequences so we have enough of them to visualize. The result is several different pieces of DNA of differing sizes and amounts. No two people have the same combination.
03.
We run your DNA through a gel
We now take these resulting strands of DNA and separate them in an agarose gel. With small pores throughout the gel matrix, the gel works like a sieve. Once the DNA is loaded into the gel, we run a current through it in a process called electrophoresis, which causes the DNA to move through the gel medium. Smaller pieces of DNA move faster than larger pieces through the gel pores. The result is a series of DNA strands, separated from one another based on size, with the largest strands on the top of the gel and the smallest bands at the bottom. This puts your unique DNA into a unique order.
04.
We stain and illuminate your DNA
The resulting gel is completely clear. There is nothing to see with the naked eye alone, but your DNA is there waiting to be illuminated. To make your DNA visible, we stain it with an ultraviolet, excitable dye called ethidium bromide. We place the stained gel on an ultraviolet transilluminator where the dye, now excited, begins to fluoresce.
05.
We capture the image
We then move a high-power, biological-grade camera into place above the UV transilluminator, and capture an image of the gel with your DNA shining through!
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That was the most detailed description I could find on their website. This raised a second question, 'What loci to the amplify with PCR?'. Which now makes me somewhat skeptical, I mean, depending on which loci they use their may only be a couple of alleles for each locus, which means your odds of being completely unique are much lower than if the whole genome was included. For example say there are only 3 alleles at each of 5 different loci that they use, thats only 125 different possible portraits, although this number increases with the use of different digestions, there are still only 125 different sequences to digest. Although that doesn't say anything about a restriction enzyme digestion, so maybe they don't do it.
I realize they say that
Quote:
We then put your DNA through a process that searches and isolates unique sequences found in your genome
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But I have a hard time believing they actually do this as it would be extraordinarily expensive, and so far I don't know of any speedy, reliable way to scan the entire genome. Then they would have to create their own primers specially for you, not that that step is hard, but for a commercial endeavor It would be much easier and more cost effective to have a standard set on hand to use. Not to mention the very large problem of not having access to every single persons complete genome to be able to say 'hey, these are unique to you and nobody else can possibly have just this sequence.'
Basically, I'm calling BS on their supposed method. I'm thinking it was probably written by a combination designer/marketing team who based it off some notes they really didn't read or understand enough to be able to say what's going on anyway.
Of course this isn't to say it's not damn cool, which it is. I would still love to have one. Of course I would be inclined to attempt my own having already done one in genetics lab. I would skip the thermal bath and just use a thermometer/hotplate/stove& pan combination. I realize this would be remarkably tedious but would work. I would also be crazy about building my own electrophoresis apparatus. This I don't think would be especially difficult either, since I could build my own AC to DC converter and the depth of the buffer is more important that the chamber construction (to a degree). UV lights are cheap enough, but ethidium bromide is toxic, and would need special disposal, which could be costly.