Since 1986, when scientist Alec Jeffreys created genetic fingerprinting, insights from DNA have transformed the modern world, from revolutionary medical treatments to the grimmer world of crime. As detailed in this excerpt from the new book “The Secrets of Our DNA: How Genetics Has Changed the World,” by professor and author Turi King, the 1994 murder of Shirley Ann Duguay in Prince Edward Island, by her estranged partner Doug Beamish, is also a landmark forensics case: the first time cat DNA was used to secure a murder conviction.
The police had impounded Shirley’s car as part of a potential crime scene: the amount of blood strongly suggested that Shirley had been the victim of a violent assault at the very least and may not have survived. The forensics team started examining the blood spatters found all over the inside of the car. Shirley was very petite, only four foot nine, and she sat on a pillow in the driver’s seat to be able to see properly — the police found the pillow near the car, also with blood on it. Analysis showed the blood was indeed human; the next thing would be to confirm whether or not it was Shirley’s.
