crime

Jerry, just remember, it’s not a lie if you believe it

414.jpg

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.

{ Forensic Science International: Genetics | PDF (2009) }

why the fuck is my ex texting me omfg go away

3.jpg

{ Oscar Pistorius’s account of events on the night that Reeva Steenkamp died }

From the air (dropped by an eagle in flight), by fire (amid the carbonised remains of an incendiated edifice), in the sea (amid flotsam, jetsam, lagan and derelict), on earth (in the gizzard of a comestible fowl)

28.jpg

On a street in Manhattan’s Lower East Side, an unremarkable gray box protrudes from a telephone pole. Inside the box lies a state-of-the-art airflow-sampling device, one part of an experiment to track how a gas disperses through the city’s streets and subway system. […]

The goal of the project is to develop a model for how a dangerous airborne contaminant, such as sarin gas or anthrax, would spread throughout the city in the event of a terrorist attack or accidental release.

The scientists released tiny amounts of a colorless, nontoxic gas at several locations around the city. The airflow samplers, located at various points throughout the city, measured the gas to determine how fast and how far it spread.

{ LiveScience | Continue reading }

unrelated { Eproctophilia is a paraphilia in which people are sexually aroused by flatulence. The following account presents a brief case study of an eproctophile. | Improbable }

Yes. I have personally torched all the evidence that proves that you are you.

429.jpg

In August 2009, scientists in Israel raised serious doubts concerning the use of DNA by law enforcement as the ultimate method of identification. In a paper published in the journal Forensic Science International: Genetics, the Israeli researchers demonstrated that it is possible to manufacture DNA in a laboratory, thus falsifying DNA evidence. The scientists fabricated saliva and blood samples, which originally contained DNA from a person other than the supposed donor of the blood and saliva.

The researchers also showed that, using a DNA database, it is possible to take information from a profile and manufacture DNA to match it, and that this can be done without access to any actual DNA from the person whose DNA they are duplicating. The synthetic DNA oligos required for the procedure are common in molecular laboratories.

The New York Times quoted the lead author on the paper, Dr. Daniel Frumkin, saying, “You can just engineer a crime scene… any biology undergraduate could perform this.”

Dr. Frumkin perfected a test that can differentiate real DNA samples from fake ones. His test detects epigenetic modifications, in particular, DNA methylation. Seventy percent of the DNA in any human genome is methylated, meaning it contains methyl group modifications within a CpG dinucleotide context. Methylation at the promoter region is associated with gene silencing. The synthetic DNA lacks this epigenetic modification, which allows the test to distinguish manufactured DNA from original, genuine, DNA.

It is unknown how many police departments, if any, currently use the test. No police lab has publicly announced that it is using the new test to verify DNA results.

{ Wikipedia | Continue reading }

Rock and roll comin’ like a rhino

413.jpg

Normally, tracking a criminal using DNA requires, at a minimum, that the perpetrator leaves behind a DNA sample in some form or other. As they are not often so accommodating, the role of DNA in crime busting, while significant, has its limits.

Applied DNA Sciences (ADNAS) has developed a new approach to solve crimes using DNA tagging. The difference is that instead of tagging the objects being stolen, they tag the pilferer with DNA. While this has been tried before by applying the DNA to a fleeing criminal with a gun, ADNAS has adopted a more subtle approach. […]

DNA Fog is an airborne suspension of artificial DNA molecules with a known but biologically inert sequence. The DNA molecules (Applied DNA’s SigNature DNA) are artificially constructed, so that a strand of DNA with 20 base pairs can have over a trillion unique combinations. A security system could use one sequence per location, one sequence for each area within the location, or even use RFID tags to instruct a sophisticated spraying device to spray a unique DNA signature for each item stolen.

Once released, DNA molecules attach onto a malefactor’s clothing, shoes, hair, and skin, as well as the objects stolen.

{ Gizmag | Continue reading }