Et qui n’est, chaque fois, ni tout à fait la même, ni tout à fait une autre

215.jpg

Prosecution is often dropped in cases largely reliant on DNA evidence when the suspect is an identical twin. The risk of convicting the wrong twin is too great.

The chance of a DNA match between two unrelated individuals is extraordinarily small — one in a billion. For siblings, the chance is 1 in 10,000. But identical twins have essentially the same DNA sequence, making the identification of the forensic evidence they leave behind extremely difficult.

But researchers at the University of Huddersfield recently developed a cost-effective and accurate method for differentiating between the genetic profiles of identical twins. The method looks at DNA methylation, a biochemical process that helps manage gene expression — turning genes on and off.

As identical twins age, different environmental factors affect their genomes, or the ways in which their genetic material is expressed. These differences can be seen in their corresponding DNA methylation. […]

The process isn’t perfect. Young twins with similar environments may not have developed significant differences in their DNA methylation. The technique also requires a large genetic sample, which may not be recoverable at every crime scene.

{ UPI | Continue reading }

related { FBI Admits Flaws in Hair Analysis Over Decades }