Aug 11, 2022

Lake Mead’s Bodies May Be Identified Using Genetic Genealogy

Citizen science and advances in DNA sequencing help identify Jane and John Does.

“Lake Stickney John Doe” spent almost a decade underwater before surfacing in June 1994 — a pair of fishermen found him among a patch of lily pads in Snohomish County, Washington.

An autopsy revealed only a few details: He had been shot in the head, likely dumped in the late 1980s and was somewhere between 25 and 35 years old.

Discovering his identity would be an uphill, if not impossible, feat. One-fifth of a nanogram — fewer than 20 human cells worth of DNA, all of it incomplete and contaminated, were recovered from the body. This, compared to a traditional cheek swab which generates between 750 and 1,000 nanograms of clean, complete DNA. The case stayed cold for over 26 years.

This summer, as lakes dry up due to climate-change induced drought, there have been an alarming number of similar John and Jane Does found — their remaining genetic material compromised after being submerged years in lakewater. At Lake Mead, four bodies have been discovered in the reservoir since May, the latest turning up on Aug. 6.

The growing sector of genetic genealogy combines advances in two distinct scientific fields — DNA sequencing and genealogy. Scientists are able to recover trace amounts of DNA to build a genetic profile and then infer familial relationships by searching databases of DNA profiles from people who have paid to have their genetic material sequenced. Though only a decade old, the method has helped solve cases where law enforcement had DNA samples, but nothing to compare them to.

You can read a lot more in an article by Christian Thorsberg published in the Grid.News web site at: