Deltanine

A new DNA technique which uses relatives' DNA to track a suspect lead to the conviction on a manslaughter charge to a man in Britain.


Craig Harman was convicted on the basis of "familial DNA searching", which linked him to the crime scene via his brother's DNA profile.


Harman threw a brick from a bridge over a motorway, which crashed through the windscreen of Michael Little's lorry in March 2003. As the brick hit his chest, 53-year-old Little suffered a heart attack, though he still managed to steer his vehicle out of harm's way before dying.


Police obtained a DNA profile of the assailant from blood on the brick but could not match it to anything on the UK's national DNA database because Harman had no criminal convictions.


Police used familial searching to uncover Harman's brother, who had a criminal conviction and was on the DNA database. His profile matched the DNA on the brick by 16 out of 20 points. This lead police to Harman, whose DNA gave a perfect match, and he eventually 'fessed up the drunken act.


Potential siblings can also be matched via the database by comparing markers. On average, two people would probably have six or seven DNA markers in common out of 20, simply by chance, however with over 12 bands in common it is rare to see unrelated people with that degree of similarity.


The moral of the story is if you want to throw bricks don't bleed on them first.