A Technological Leap Answers a Decades-Old Question
With Rasmussen’s and his relationship identities solved, three mysteries remained, and the biggest challenge was retrieving usable DNA from the remaining Bear Brook victims. “We did two or three extractions from bone, and a liver extract, and what little we could get was very low quality. In the first sequencing, the amount of human DNA was only 2 percent — the rest was bacterial. Theoretically, you could amplify that, but only at extraordinary expense.”
Then, Dr. Rae-Venter remembered reading about a case where atDNA was obtained from rootless hair for the first time, using technology developed for use by paleontologists.
Nobody had ever gotten atDNA from the hair shaft before.” Dr. Rae-Venter explained that as hair grows, the cells undergo apoptosis, or programmed cell death. As that occurs, the nuclear DNA gets chopped up. The fragments are so small, some of them are only about 45 base pairs, and even polymerase chain reaction (PCR) techniques can’t detect atDNA in the hair shaft.
“I contacted the lab and they agreed to test hair from the Bear Brook victims, which, luckily, was plentiful. After adding a bleaching step to remove the melanin that interferes with DNA extraction, 10 strands of the woman’s hair was sent to the lab. Because the nuclear DNA fragments were so tiny, whole genome sequencing was performed and an algorithm applied, extracting enough data to create a file uploadable to GedMatch.”
Thirty-three years after the crime, breaks in the case are happening fast.
On Nov. 13, 2018, Dr. Rae-Venter uploaded the adult victim’s DNA profile to GEDmatch. “I got the results at 6 a.m. the next morning and identified her by 8 through a second-cousin match. All because of atDNA from rootless hair.
“Extracting atDNA from the hair shaft was not possible before,” she emphasized, adding that final identification must still be confirmed by DNA testing of a family member. “The implications of this technology for solving cold cases worldwide are just
huge.”
Dr. Rae-Venter uploaded the youngest victim’s profile that Thursday. “I’m sure she will be part of the same family.”
Much more info at link:
We Are Data - The Finders: Cracking Cold Cases with Genealogy, Forensics, and DNA - Part Two of A Two-Part Series
BBM.