Genetic Genealogy can Help Solve Cold Cases. It can also Accuse the Wrong Person.

According to an article by Nsikan Akpan, William Brangham, and Rhana Natour published in the PBS News Hour web site:

“From a law enforcement perspective, the case for using genetic genealogy is strong. But experts are also flagging concerns about what the method means for people’s legal and DNA privacy.”

Here is a quote from further in the same article:

“Genetic genealogy — in truth, any forensics dependent on DNA — can fall prey to the same human biases that plague other aspects of law enforcement. Close relatives or even non-relatives can be accused of the crime if care is not taken with how the genetic genealogy is interpreted.

“It happened to Michael Usry.”

The article then goes on to describe GEDmatch, the work of genealogy expert CeCe Moore, the FBI’s Combined DNA Index System (called CODIS), and the case of one person who was detailed by police for suspicion of murder although he was eventually cleared and released. The same article also states:

“Even though autosomal genealogy — with its 700,000 letters — offers a much more specific portrait of a person, it can still lead to false identifications. Ancestry tests can be misinterpreted, and a direct-to-consumer DNA profile can contain errors — typos in the book. A small study in 2018 found up to 40 percent of the SNPs identified in DNA profile might be false positives, a result mirrored by a second study published this June.”

Also:

“The science there is much less well-developed and we need to be very careful about relying on it to target people,” Berkman said. “There is a case in Germany where they thought that the DNA evidence from a murder scene pointed to a certain ethnic minority, and then [law enforcement] went and harassed that population.”

The article also refers to a PBS program describing people who have taken DNA tests and as a result been inadvertently involved in murder investigations because of genetic genealogy. You can watch an online video of that program at https://youtu.be/wkZ8RERRJy4.

The same article also contains a video of CeCe Moore explaining how at-home DNA tests and genetic genealogy helped solve a 30-year-old murder.

You can read “Genetic genealogy can help solve cold cases. It can also accuse the wrong person” at: https://www.pbs.org/newshour/science/genetic-genealogy-can-help-solve-cold-cases-it-can-also-accuse-the-wrong-person.

5 Comments

The Michael Usry case was a one off that happened a very long time ago using old outdated low refinement Y-DNA testing. That situation cannot happen now because we use autosomal DNA that compares hundreds of thousands of markers rather than just 36. Although the first PBS episode referred to was very good indeed, part of the second episode made untrue assertions caused by sloppy journalism that resulted in retractions and corrections having to be made.

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Good article but would need to be summarized for many people.

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Because genealogy DNA does NOT have a legal chain of custody, it cannot be used as evidence; only as a clue to identify suspects – think “mug book” or police artist sketches or eyewitnesses or many other kinds of clues. With DNA, the police compare a suspect’s actual DNA to a sample found at the crime scene. Genealogy DNA is just a clue to possible suspects.

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That comment “up to 40 percent of the SNPs identified in DNA profile might be false positives” is taken way out of context. If that were true, even parent/child comparisons would not work, much less comparisons of 2nd or 3rd cousins. The statistic refers to extremely rare variants.

https://www.biorxiv.org/content/10.1101/696799v1

The abstract for the same article states “SNP-chips are an accurate and affordable method for genotyping common genetic variants across the genome.”

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I agree with the comments that Ann and Trevor have posted. I hope that you will publish a correction since many people who read the article won’t have seen the comments, and some subscribers to your newsletter will have only read the misleading headline.

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