Feature CRIMEFIGHTING WITH FAMILY TREES Parabon Nanolabs shot to fame in a controversial field, using DNA and genealogy analysis to catch criminals. Then it hit a setback. By Carrie Arnold t was May 2019 when Parabon Nanolabs traces of blood at the scene, and the detective ran into a major controversy. At the time, in charge of the case, Mark Taggart, made a it was the most famous forensic-genetics personal plea to GEDMatch’s founder, Curtis company on the planet. From its head- Rogers, for access to the database. When it was quarters in Reston, Virginia, Parabon was granted, Parabon, which had initially refused helping police to crack cold-crime cases the case, signed on. The company traced sev- almost weekly, such as the murder of a eral partial DNA matches to individuals liv- Traces of crime-scene DNA have been matched to suspects using genealogy databases. Canadian couple in 1987 and the case of ing in the area, and narrowed in on a suspect, Ia young woman who was sexually assaulted a teenaged boy who was a relative of one of company and with GEDMatch data from peo- and killed in the 1960s. them. Taggart made an arrest. ple who have opted to allow its use in criminal The company had made its name by com- That triggered an immediate backlash from cases. paring suspects’ DNA to profiles on genealogy genealogists, privacy experts and the wider Just as the prominence of forensic genetic databases and piecing together family trees to public at the violation of GEDMatch’s agree- profiling has grown, so has its notoriety. Eth- track down alleged offenders. ment with its users. In response, Rogers icists have raised concerns over China’s use But then controversy erupted over a case required the site’s millions of users to specifi- of genetic profiling to target the Uyghurs, a Parabon helped to solve, in which a teenage cally opt in to law-enforcement use. Overnight, predominantly Muslim minority population boy had violently assaulted a septuagenarian Parabon lost its major source of DNA data. in the country’s northwestern provinces. In in a Mormon meeting house in Utah. The Utah That proved to be a challenge for the com- the past year, the US government has launched case generated public backlash because of pany, and for forensic genetic genealogy. In two programmes that have begun taking concerns over privacy. the year since then, the restrictions on GED- DNA samples from immigrant detainees and Genealogists at Parabon had been generat- Match’s data have forced Parabon to forge some asylum seekers. The US Department of ing leads by sifting through a database of DNA ahead while navigating new controls limiting Justice issued guidelines last November that tests called GEDMatch, a free-to-use website access to genealogy data. It has also continued tried to set boundaries on the use of forensic that allows users to upload test results in the work on another strategy: attempting to use genetic genealogy, but concerns about police hope of finding long-lost relatives. At the time, DNA to reconstruct faces. At the same time, it is brutality and systemic racism against Black GEDMatch allowed law-enforcement agencies facing competition from forensic-geneaology Americans have raised questions as to whether access to the profiles to help solve murders companies that are trying to stake their own these guidelines provide enough protection and sexual assaults, unless users specifically claims in the field. to people of colour, who are disproportion- opted out. The police, aided by Parabon and Parabon acknowledges that the rule change ately stopped by police and overrepresented companies like it, made new arrests weekly. at GEDMatch substantially restricted its main in criminal DNA databases. These legal, ethical But the Utah case was not a murder or a source of DNA data, but it says this was a tem- and social concerns have left industry experts sexual assault — and so was not covered by porary setback. It adds that it has continued to wondering what’s next for forensic genomics. the website’s disclaimer. The assailant had left solve cases using data from another genealogy “Because DNA is so powerful, we tend to see 178 | Nature | Vol 585 | 10 September 2020 | Corrected 23 September 2020 ©2020 Spri nger Nature Li mited. All rights reserved. ©2020 Spri nger Nature Li mited. All rights reserved. Then, she moved forward in time to trace their descendants, focusing on California during the time the crimes were committed. After two months, Rae-Venter handed the detective the names of three brothers. DNA from a cigarette discarded by one brother matched the sam- ple, and on 24 April 2018, police arrested Joseph DeAngelo — in the first criminal case to be solved using the technique. (DeAngelo pleaded guilty to multiple counts of rape and murder and was sentenced to life in prison last month.) Following DeAngelo’s arrest, forensic genetic genealogists such as Rae-Venter and CeCe Moore (who joined Parabon in May 2018) helped to solve similar rape and murder cases at a rapid clip. Although a few ethicists raised concerns about privacy, media coverage of the cases was overwhelmingly positive. “I was actually surprised there wasn’t more criti- cism,” says geneticist Ellen McRae Greytak, bioinformatics chief at Parabon. And then the Utah case hit the media, and the criticism came crashing in. Active case Late on Saturday 17 November 2018, 71-year- old Margaret Orlando dialled 911 from a Mormon meeting house in Centerville, Utah. Someone had thrown a rock through a window, climbed in, and attacked her as she was practis- ing the organ, strangling her until she passed out. Taggart was called to the scene, where he found three drops of blood, presumably from her attacker having cut himself on the broken glass. The DNA profile didn’t match anyone in state and federal databases, but a chance conversation with a genealogist friend Traces of crime-scene DNA have been matched to suspects using genealogy databases. gave Taggart hope: if police couldn’t identify the suspect, perhaps they could track down a it as a silver bullet,” says Yves Moreau, a biol- share small portions of DNA. This allows con- relative. He reached out to GEDMatch and got ogist and engineer at the Catholic University sumer genetic-testing companies such as permission to use the site. of Leuven in Belgium. But law-enforcement Ancestry in Lehi, Utah, and 23andMe in Sun- In the same way that Rae-Venter helped to agencies are using databases and techniques nyvale, California, to estimate relationships identify the Golden State Killer, Parabon pro- not designed for solving crimes or generating between two individuals who have submitted vided Taggart with three possible names, one leads, he says. “It’s like a knife — people under- samples, as far out as fourth cousins (who of which he recognized right away. The man, estimate just how sharp they can be.” share a pair of great-great-great grandpar- who lived near the meeting house, had had ents). Anyone can upload the results of their several run-ins with the police, and Taggart Family ties own DNA test to databases such as GEDMatch. discovered that he had a 17-year-old nephew In December 2017, genetic genealogist Barbara Rae-Venter found two GEDMatch pro- living with him — a nephew who matched the Rae-Venter got the call that would propel files that looked to be distant cousins of the description the organist had given. family-tree forensics into the public eye. She suspect, and used that information to work The next day, Taggart managed to get a DNA was running a business that used GEDMatch backwards and find their great-grandparents. sample from a milk carton the suspect had to find clients’ long-lost relatives when she thrown in the rubbish at school. It matched. heard from a California detective who had So did a follow-up swab. Taggart arrested the found some old DNA evidence and was trying suspect (whose name was not disclosed as he to reopen the case of the Golden State Killer, was a minor) on 24 April 2019 — one year to the a serial rapist and murderer who committed a day after the arrest of the Golden State Killer. string of crimes in the 1970s and 1980s. “It was like a puzzle coming together,” he says. Combining DNA samples with family trees WE’RE STILL ASKING With the relief, however, came the publicity. is the core of forensic genetic genealogy. The WHETHER THESE “We were a little surprised at how positive the process rests on the simple statistical rules of response was to the Golden State Killer and genetics. A parent and child, or two siblings, TECHNIQUES ARE how negative the response was to this,” Greytak share 50% of their DNA. Grandparents and says. She points to a study in PLoS Biology1 that JOCHEN TACK/IMAGEBROKER/ALAMY JOCHEN grandchildren share 25%. Even distant relatives SCIENTIFICALLY VALID.” found 90% of Americans supported police use Corrected 23 September 2020 | Nature | Vol 585 | 10 September 2020 | 179 ©2020 Spri nger Nature Li mited. All rights reserved. ©2020 Spri nger Nature Li mited. All rights reserved. Feature sent a sample with just 1 nanogram. Everyone involved — including Armentrout and Greytak — was surprised to find that it worked. Parabon says it can now sequence enough SNPs to trace family history and build a face with less than 1 nanogram of DNA. Greytak says that the sequencing runs that use such scant quantities of DNA often leave parts of the genetic code blank because the sample is too degraded or too dilute to read.