Re: DNA evidence countermeasures?
At 07:50 PM 1/28/03 +, Ken Brown wrote: ... Think - you are a suspect. They find 2 human DNA signals at the scene of the crime, one from you, one from someone quite different from you. Well, they can look for the other guy in their own time, but they've got you. If they are using a stringent enough test (often they don't) the odds against it not being you are huge. Yep. Imagine leaving twenty random peoples' fingerprints at the scene along with your own. You might confuse the police for awhile, but eventually, they'd find the set of prints that matched with the suspect they were holding The creepier thing here is the possibility of planting DNA evidence, which seems very easy to me. It wouldn't be a big surprise if this had been done by now. A really careful investigation might detect the fraud, but if the planted evidence points in a really plausible direction anyway (e.g., the apparent murderer is the husband/ex-husband/disgruntled business partner/drug dealer of the victim), it may be hard to get anyone to take a second look at the data. The scary number of death-row inmates who've been more-or-less proven innocent by DNA evidence implies that the police, prosecutors, judges, and juries just aren't all that careful about checking the plausibility of evidence anyway. ... --John Kelsey, [EMAIL PROTECTED]
Re: DNA evidence countermeasures?
At 07:50 PM 1/28/03 +, Ken Brown wrote: Thomas Shaddack wrote: But now how to avoid leaving random DNA traces? What about giving up on NOT leaving traces and rather just use eg. a spray with hydrolyzed DNA from multiple people, preferably with different racial origin, Get some scurf from expensive D.C. restaurants. PCRAmplify it up if you want, that will create some diversity too. Just a corollary of someone's idea to put Santa on his own naughty-list. Major Variola's Brand Homogenized Human DNA The Finest Homogenized Human DNA CounterForensic Science Can Produce HHDNA From Our *Competitors* Uses the **Same, Well-Known Donors** Over Over **Our HHDNA raw material is collected in the Wild from Unknowing Donors** **We collect in a large urban setting, which has very large DNA marker diversity** All of Major Variola's Fine Products are Not for internal use Available in a Cypherpunke Shoppe near you! See also our line of Martha Bill Stewart spring fashions featuring a special UV-emitting lining on the *inside*.
Re: DNA evidence countermeasures?
On Tue, 28 Jan 2003, Major Variola (ret) wrote: Get some scurf from expensive D.C. restaurants. PCRAmplify it up if you And be sure to open it -only- at the crime scene. If the investigator could grab a sample of the same mix of DNA at some other location that the suspect visits then they'd have a clue that the scene was tampered with. As always, you must look at both 'traffic analysis' and 'signature analysis'. Major Variola's Brand Homogenized Human DNA Some other factors: - With sufficient motivation it would be possible for the police to keep a running sample of most public places. Exactly what would drive such a utility function isn't clear. Perhaps an assassination of a high dignitary or major theft. If they could track a suspects last few days it would be possible for them to take comparative samples. - Never spit or otherwise leave phsical evidence in public (ie trash recepticles as public eating places) so that a sample can be taken without a search (at least technicaly it wouldn't be a search). There are cases of cops following suspects for several years and finally catching them by simply grabbing a spit sample off the sidewalk (there is a real world example I posted in the archives a couple of years ago). - If you're going to commit crimes where physical genetic evidence may be problematic then be sure to have taken a good shower and a fresh haircut (if it wouldn't be incriminating). Make sure your clothing is freshly washed and has been touched by nobody who has regular interaction with you. This means a clothes cleaner you don't normally use (don't use a credit card or a real name/number). If possible get somebody else to pick up the clothes (there are cameras everywhere). - Wear complete coverage clothes, sort of like those sleepers you wore as a kid only with gloves and booties. This would include a face mask. - Wipe the outside of the outfit off with something that is a very good agent at breaking down DNA, carry a spray bottle of this same agent. Spray it liberally. - It might be worth making the outside of the suit slightly tacky so that it tends to pickup instead of shed material. This may imply wearing several layers and shedding them once in a while. - Be sures that there is nothing in ones background that would indicate they have necessary knowledge, motivation, or ability in this regards. - This all implies a lot of preperation and time that is not constrained. Having large gaps in ones schedule at convenient times would be indicative. It's worth noting again that one of the major threats to anyone building such a database of genetic data is the continued denial of that same technology to the public at large. If genetic technology expands until it's reasonably easy to have scans and splices done then keeping a databank of individuals DNA is worthless. Personally, I believe that this is the reason that cloning and such are being hounded into illegality by secular authority. Once somebody has a legally recognized clone walking around (or clones that are unknown or unregistred) any such DNA evidence is worthless. -- We are all interested in the future for that is where you and I are going to spend the rest of our lives. Criswell, Plan 9 from Outer Space [EMAIL PROTECTED][EMAIL PROTECTED] www.ssz.com www.open-forge.org
Re: DNA evidence countermeasures?
On Tue, 28 Jan 2003, Thomas Shaddack wrote: Watching local TV, a police brass with three stars is talking about DNA (Using deeper-penetrating techniques it should be possible to do things like permanently change skin color, eg. by disabling or stimulating melanine production, or even achieve a chameleon-like effect. Or selectively applying the change using a method similar to tattoo, just using a retrovirus vector instead of ink. Genetics WILL be used in cosmetics once the technology will become safe/cheap enough.) Just musing, and curious if/where I have errors in my ideas... It boils down to the concept of identity. Our white blood cells are programmed to know an individual identity - the chemical equivelent of self. If you mess with that, you're going to have some serious physical problems. You could change everything, so it stays consistent chemically but changes physcially. Does the thinking process change too? Sounds like a cool sci-fi story for now, but I think you are right - in a few years it'll be happening. Patience, persistence, truth, Dr. mike
Re: DNA evidence countermeasures?
Thomas Shaddack wrote: But now how to avoid leaving random DNA traces? What about giving up on NOT leaving traces and rather just use eg. a spray with hydrolyzed DNA from multiple people, preferably with different racial origin, thus still leaving fragments like hair or skin cells, but contaminated with wild mix of DNA, so the PCR-copied mixture will be unusable for reliable identification? Nope. Already they have DNA from all over in the sample. Bacteria if nothing else. Probably other humans. So if something from you matches something there, you are spotted. If you were trying it on you would do best to spray around DNA from a close relative so they can't tell the difference. Think - you are a suspect. They find 2 human DNA signals at the scene of the crime, one from you, one from someone quite different from you. Well, they can look for the other guy in their own time, but they've got you. If they are using a stringent enough test (often they don't) the odds against it not being you are huge. But if they have 2 almost-but-not-quite different sequences - well, how can they be sure tht the one that looks like yours isn't really the other one amplified badly (which happens)? NB - the vast majority of forensic DNA evidence is used to support the defence.
RE: DNA evidence countermeasures?
Thomas Shaddack[SMTP:[EMAIL PROTECTED]] Watching local TV, a police brass with three stars is talking about DNA evidence. Losing samples of DNA is quite inavoidable; hair falls out, skin peels, all you need to get for positive identification is one single cell. [...] Go and watch Gattaca
DNA evidence countermeasures?
Watching local TV, a police brass with three stars is talking about DNA evidence. Losing samples of DNA is quite inavoidable; hair falls out, skin peels, all you need to get for positive identification is one single cell. After collecting the sample, you amplify it (create much more DNA molecules) using PCR (polymerase chain reaction), making lots of copies of the DNA molecules in the sample. Then you take the mixture, split the huge molecules to smaller fragments using enzymes (I hope I remember it well), and then separate the fragments using eg. electrophoresis. Then you spray the gel strips with something that binds to the DNA fragments, light it with UV lamp (which causes the DNA stripes to shine), and get a photograph that resembles bar code. Then you compare the bar code with the reference samples. This is the old approach used typically for tests in eg. paternity lawsuits. I suppose there are newer, more modern, faster automated methods, but the principle should be the same. But now how to avoid leaving random DNA traces? What about giving up on NOT leaving traces and rather just use eg. a spray with hydrolyzed DNA from multiple people, preferably with different racial origin, thus still leaving fragments like hair or skin cells, but contaminated with wild mix of DNA, so the PCR-copied mixture will be unusable for reliable identification? In the future, when gene therapies will be well-mastered and common, it should be possible to introduce entire new genes into the skin cells themselves; if they will not penetrate too deep into the skin, the modified cells will grow away later in time. The viral vector could be administered as eg. a spray or a bath. (Using deeper-penetrating techniques it should be possible to do things like permanently change skin color, eg. by disabling or stimulating melanine production, or even achieve a chameleon-like effect. Or selectively applying the change using a method similar to tattoo, just using a retrovirus vector instead of ink. Genetics WILL be used in cosmetics once the technology will become safe/cheap enough.) Just musing, and curious if/where I have errors in my ideas...
Re: DNA evidence countermeasures?
At 07:13 PM 1/28/2003 +0100, Thomas Shaddack wrote: But now how to avoid leaving random DNA traces? What about giving up on NOT leaving traces and rather just use eg. a spray with hydrolyzed DNA from multiple people, preferably with different racial origin, thus still leaving fragments like hair or skin cells, but contaminated with wild mix of DNA, so the PCR-copied mixture will be unusable for reliable identification? There indeed might be a DNA mix-master business, like for urine samples, that could be sold on-line. A few of the things that can interfere with PCR testing: - hair pigments - dyes from denim - proteins in the evidence sample can retard the migration of DNA fragments in gels (a problem known as band shift) - Powdered gloves may leave a residue on evidentiary material, which may interfere with DNA analysis. - Small Particle Reagent (SPR), a suspension of molybdenedisulfide powder in a detergent solution, used for fingerprint detection on wet, oily, or dirty surfaces, is a destructive method, and will interfere with just about every other forensic examination that may be required. - Exposure of DNA to external agents such as heat, moisture, and ultraviolet radiation, or chemical or bacterial agents. Such exposure can interfere with the enzymes used in the testing process, or otherwise make DNA difficult to analyze. steve
