Scientist extracts DNA from rootless hair killers
The image of a detective collecting cigarette butts, lint and hair strands populates the popular imagination and transports himself to forensic reality through modern techniques that extract, from this evidence, DNA from both the victim and the perpetrator. In the first two cases, saliva and skin carry the genetic charge of the body that generated them; In the third, however, good luck has to smile at the researcher in the shape of the hair root: no root, no DNA.
Extracting the genetic profile of a broken strand was impossible - at least until a University of California paleogeneticist developed a technique for retrieving and sequencing DNA from any part of the hair. Ed Green is known within the scientific community for his work in sequencing the genes of the Neanderthal man - his merit for having identified, from a 38, 000-year-old bone, the first complete ancestral genome.
Work helped to close case opened in 1985
Since mid-2017, he has been quietly cooperating with the police to, using the technique employed on man's ancestors, extract genetic profiles and thus give a face to murderers, help solve outstanding crimes and identify unnamed victims.
Green often receives (always in hand) packages containing hair found at crime scenes. Some are serial killers acting for decades without the police getting the slightest clue about their identity; others are victims still without a name.
He entered the criminal world at the hands of genetic genealogist Barbara Rae-Venter, known to the general public for discovering the identity of the Golden Gate Killer, serial killer responsible for 45 rapes and 12 murders from 1979 to 1986. In 2017, she collaborated with New Hampshire police identifying a woman and three girls whose bodies were found inside barrels in a park. After decades virtually in the open, everything that could have DNA had already been degraded.
The solution was on the bench in Green's lab, which created in 2005 a technique for extracting DNA from fossilized bones. Adjusting the process for hair use took about a year. After finishing work on the strands of unidentified New Hampshire corpses, Green felt nothing different - until she heard the names of Marlyse Elizabeth Honeychurch and her two daughters, Marie Elizabeth Vaughn and Sarah Lynn McWaters (one child still left). identify).
"I felt like the inventor of a rocket to go to the moon and then watch it on TV, landing on lunar soil, " he recalls.
Use of DNA by innocent people generates controversy
Using the DNA profile found in genealogical databases (ie, relatives of criminals), however, has raised controversy about the validity of the method. Still, Green expects his process to be used for good. Forensic scientist Suzana Ryan, who recently sent him the embalmed head of a woman who has yet to be identified, shares this desire.
According to her, there are 200, 000 to 250, 000 cases waiting for a solution in the US alone. Even if the hair was collected only 10% of the time, there are 20, 000 cases that can be solved. But neither believes that the technique will be widely adopted: besides being expensive (single-strand sequencing costs thousands of dollars), the process still needs a genetic genealogist to find the family origin of DNA.