Until very recently touch DNA was not even allowed into court. Many countries still dont allow it. In fact touch dna is used more often in clearing someone of a crime then it is in aiding in a guilty verdict (unless there is enough corroborating evidence to support it). Its not reliable enough, what with the very real possibility of contamination. The possibilities of secondary or even further transfers are to high. This leaves a guilty verdict based on Touch DNA open for appeal (which is what the Rs would have done had this gone the other way). Dont worry, I came armed..
So lets say the Rs are at the Ws Christmas party, shaking hands, hugging, touching serving spoons and plates, making drinks and taking drinks handed to them, opening gifts (gifts that had been in stores, touched by how many people I cant even guess, wrapped in paper also from a store and you get the idea, its limitless)... There was so much transfer that night you probably could have made a whole human being from it. The point is, it doesnt matter that it was there, its not even a big deal that it was, what does matter however is how it got there, you have to know that before you can say that it belongs to a killer. Until you know that, its just as likely to be innocent transfer. Its a 50/50 shot and with all the other evidence taken into consideration I'd say IDI's shot is about as big as the samples that were tested...
Touch DNA
Edited by Dr. Maher Noureddine, forensic DNA expert
So, when the SBI lab or investigators refer to touch DNA, you should think very small amounts of DNA. With touch DNA, physical contact is sometimes assumed or hypothesized. Therefore, you should also think about the physical environment from which this evidence was collected. Always consider alternative explanations for why someones DNA would be expected to be found in a given area or on a given surface.
Because such a small amount of evidence is being analyzed (as few as 5-10 cells) contamination and transfer of DNA are issues that should be considered through each step in the analysis. Evidence collection , extraction of DNA, amplification and interpretation are four areas where attorneys should be aware of possible problems.
http://ncforensics.wordpress.com/2011/07/21/touch-dna/
Touch DNA Resources
As to how likely it is that an innocent touch of a person or object will result in a DNA transfer, the variables are numerous. In fact, some individuals just tend to shed their DNA more than others. This can be a biological variable or behavioral (think more sweating, more face rubbing, etc.). All things being equal
.the more time a person is in contact with something, the more DNA they will likely deposit. However, consider an example of two people, each wearing a different ski mask for the same period of time. Will they leave the same amount of DNA? Of course not.
To demonstrate how easily DNA can transfer via innocent means, one need look no further than the forensic DNA laboratory. Extraordinary measures are used to ensure that among other things, the analysts DNA does not contaminate evidence they are working on. I can tell you that it happens, and more often than you might think. It does not mean that the analyst is terrible, it is just a testament to the ubiquitous nature of DNA and how easily it can be transferred. Of course, if this is occurring in laboratories, remedial steps must occur to limit the chances of it happening again.
http://forensicdnaconsulting.wordpress.com/
I have more kids but I'll leave it at this for now.....
. But all of that is just super silliness. Whereas the touch DNA stuff is a sure thing. :facepalm:
