DNA can be faked: Authentication of forensic DNA samples
Date of the article: June 2009
After extraction from cells in a sample of tissue or contacted material, DNA is amplified by induced replication and specifically treated; according to its individuality, it produces then a unique pattern for each person, who may be identified or excluded by comparing to another sample or database. A very small sample, even deteriorated, may be enough to identify a person. This technology has already allowed the release of tens of condemned innocents from jails, but hasn’t avoided the execution of false guilty in the past…
DNA technology is fast evolving and its full potential is yet to discover. One of the applications it may have is biometrics and irrefutable, easy and fast people identification, which in turn has various civil rights’ implications and is prone to a multitude of questions. If the DNA is a never ending promise for humankind, it may well also become a powerful tool in the hands of envious sectors of society, or escape democratic control, which by the way in this case, is not even a guarantee of freedom and human rights for everybody.
One of the most worrying issues about DNA, not yet much discussed neither in the scientific community nor among politicians and society, be them progressive or conservative, is the faking of DNA. In a time when the civil rights are easily suspended in democracies such as the USA and many of its allies, obscurant state authorities intervene in the life of the nations,and the death penalty persists around the world reinforced by "irrefutable evidence" against acused, the EU is setting up plans to build a central data base with biometric data, and some people discuss the hypothesis of genetic testing on migrants, we reproduce here a very recent scientific article we found valuable to open up this issue out of the closed doors of lab’s. Although relatively complex, we found it to be interesting to show objectively how a technology so undoubtable recognized as mature and absolutely safe, brings about serious issues, once more, as in the past.Who controls the chain of investigations? What means has the defense? Whose know-how is accessible for minorities? How to avoid sophisticated manipulation?
We also wish to lift up your curiosity and stimulate the forwarding of the text.
The left is often criticized for being demagogic and destructive, not having material and true data to support its criticism and proposals. This time we go to the lab’s bench.The article follows.
Tip: pass over "Materials and methods"
Abstract
Over the past twenty years, DNA analysis has revolutionized forensic science, and has become a dominant tool in law enforcement. Today, DNA evidence is key to the conviction or exoneration of suspects of various types of crime, from theft to rape and murder. However, the disturbing possibility that DNA evidence can be faked has been overlooked. It turns out that standard molecular biology techniques such as PCR, molecular cloning, and recently developed whole genome amplification (WGA), enable anyone with basic equipment and know-how to produce practically unlimited amounts of in vitro synthesized (artificial) DNA with any desired genetic profile. This artificial DNA can then be applied to surfaces of objects or incorporated into genuine human tissues and planted in crime scenes. Here we show that the current forensic procedure fails to distinguish between such samples of blood, saliva, and touched surfaces with artificial DNA, and corresponding samples with in vivo generated (natural) DNA. Furthermore, genotyping of both artificial and natural samples with Profiler Plus1 yielded full profiles with no anomalies. In order to effectively deal with this problem, we developed an authentication assay, which distinguishes between natural and artificial DNA based on methylation analysis of a set of genomic loci: in natural DNA, some loci are methylated and others are unmethylated, while in artificial DNA all loci are unmethylated. The assay was tested on natural and artificial samples of blood, saliva, and touched surfaces, with complete success. Adopting an authentication assay for casework samples as part of the forensic procedure is necessary for maintaining the high credibility of DNA evidence in the judiciary system.