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Briefcase Sized DNA Analysis System
An anonymous reader writes "Japan's NEC Corporation along with Aida Engineering have developed a briefcase-sized DNA analysis system that enables the police to perform comprehensive DNA testing at crime scenes in as little as 25 minutes. The same test would take at least a day to a week (if re-testing or conformation is required) in the lab. The system is compact enough to be carried to crime scenes or other locations where quick DNA analysis is required, making it the world's first portable DNA analysis system."
Can't wait to see the minimum-wage TSA employees using this.
Coming soon! To an airport near you!!
No folly is more costly than the folly of intolerant idealism. - Winston Churchill
and I wouldn't mind sharing my DNA with the girl in the photo.
The higher the technology, the sharper that two-edged sword.
So now the police can tamper with the evidence at the scene, rather than having the lab do it.
From the blurb:
The same test would take at least a day to a week (if re-testing or conformation is required) in the lab.
Um, correct me if I'm wrong here, but the 1-7 days is still gonna be the case if/when you're verifying your results. This is just a "quick and dirty" test that will gain more acceptance and weight that it will deserve (::cough::POLYGRAPH::cough::). My guess is that it will just be a tool that Homeland Security/Your Average Cop will use to hold you until other tests *conclusively* provide a definite presence/absence answer (like PCR done by an ISO certified lab, HPLC done by an ISO certified lab, GCMS done by.. well you get the point.)
Just my $0.02 here.
E = m * c^(Hammer)
khasim (12/9/06): In a blind taste test, more people preferred Coke over the Pepsi that I had previously pissed in.
I imagine they can do it in the time they say. I also imagine the results are very simple, like looking at one STR sequence and counting how many lengths of it are in the person's genome in a process similar to qPCR, less RFLP/southern, as parent seems to think. Despite what TFA might imply, I don't think there's endonuclease digestion involved. I may be wrong, and they could have a really, really fast breifcase thermocycler making this work. Maybe, doubt it.
I'm not any kind of STR expert, but from cribbing Wikipedia http://en.wikipedia.org/wiki/Short_tandem_repeat, here's my impression of what's going on with this kit:
1. get cells = blood and semen. yum. In fact, I'd infer this kit is probably a "semen-only" deal in practice, which makes isolating the DNA that much easier, since semen is largely DNA.
2. isolate DNA. Do it yourself, kids! (http://learn.genetics.utah.edu/units/activities/extraction/) 2-5 minutes with a kit.
3. PCR. Here's where things get interesting. What are their primers? I think they're using 5-10 nucleotide STR sequences that are already conjugated to a fluorescent dye. Since STRs for human identification use are just, according to wikipedia, 4-5 STRs (10-50 nucleotides) long, each cycle can probably be as short as 30 seconds. With ramping the temperatures we can call that 1 minute per cycle. How many cycles do we need? 10 cycles gives us 2^10 copies of the original STR, that's (biologist math)1000 copies(/biologist math). Add 2 minutes for our hot-start polymerase, and that's 12 minutes for PCR. Whoo! It well may be less, i.e. shorter elongation, fewer cycles. This is where they're claiming to save time, so who knows.
4. electrophoresis. Undoubtedly capillary, you can see it in the photo (at least I can), and since we're looking at stuff that's only 75 nucleotides max, can be done very quickly. I don't really know capillary gel electrophoresis, but it apparently kicks the shit out of slab gel electrophoresis: http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=330505. We'll call that 10 minutes, lol. Could be a bit more? Balances with the PCR.
5. Of course, we added a 10-100 nucleotide standard conjugated to a different fluorescent species from the primers (i.e. the primers glow green and the standard glows red), so we can use our shitty little built-in 2-wavelength spectrophotometer to see where our unknown sample's bands are.
And now we have our data! And that only took... 25 minutes! Of course, this isn't a full-blown RFLP, like parent seems to assume. But just for doing a quick-and-dirty count of STRs, this could work. That's how I'd do it. Maybe I just invented a competing type of kit, lol. In any event, looking at the picture, I get the feeling their pipettes are crap.
Note this doesn't show how many repeats of a given legth the accused has, so the asshole could have 3 5-repeat ones and 2 4-repeat, and the machine would show that as being the same as a person with 1 of each. Also, they may use more fluorescent dyes to look at more STR sequences without too much difficulty. But in general, the samples will be unclean at best, total crap more often than they'll like to admit, and, in the end, only good as a blood-type-and-then-some test. How juries will react to this, I don't know.
To get even farther from parent, the real threat to your privacy is coming from gene chips, the next generation of sequencing technology. This kit is comparatively rudamentary, and obviously expensive. Yet more overhyped crap, whee!
Indeed, I had a lecture from the director of our national forensic institute (Dutch) once, explaining the whole procedure of obtaining DNA, what they actually analyze and how they verify the validity. There is a reason why these tests take up to 2 weeks to give a result: Once you as a scientist say "we have DNA evidence, we got him!" it pretty much seals the deal. So you got to be damn sure you are right: -what are the odds that an identical DNA pattern from someone else came there (no they don't sequence your DNA, so there's a small chance that another person with a similar pattern was on the crime scene, usually the chance is close to zero though) -how was the evidence collected, could it be contaminated etc. etc. -is there other evidence that contradicts the results And after that an analyzis has to been done estimating the chances that you are wrong in saying that the DNA is from the person you are accusing, and that he/she actually commited the crime. I wouldn't be very happy to let an untrained (in forensics) police officer do those things, because most of them hardly known what DNA is, and what exactly is analyzed. Another reason why you wouldn't wnat that: in the lab everythinh is done anonymous, the analyst just has sample numbers and suspect, X, Y, and Z. The police will know the name of the suspect and stop looking as soon as they think they can nail him, regardless of the presence of any other evidence contradicting this. PS. This forensics guy wasn't too happy with CSI, it creates really unrealistic expectations about what cases the police can actually solve (and the amount of time it takes them to do so).