According to a latest report over 60 percent of the Americans’ ancestry can be traced through existing DNA databases. This includes even persons who have never submitted their DNA for evaluation say researchers because enough individuals have already submitted their genetic information. The latest study revealing this was published in the journal Science.
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The researchers said that there are several public genetic databases that contain DNA information. For example in the case of the “Golden State Killer”, the police nabbed the killer – a former police officer Joseph DeAngelo. One of his cousins had taken a commercial DNA sequencing test and the information had led the police to DeAngelo whose DNA matched with those from the samples found in the crime scenes of murders and rapes all over California.
The team of researchers at genealogy website MyHeritage and at Columbia University in New York who wrote this latest study said that the police are using these databases as tools to catch the miscreants. In fact within April to August this year, 13 cases were nabbed using DNA from familial connections. “Most of these investigations focused on cold cases, for which decades of investigation failed to identify the offender. Nonetheless, one case involved a crime from April 2018, suggesting that some law enforcement agencies have incorporated long-range familial DNA searches into active investigations,” they explain.
For this study Yaniv Erlich, chief science officer of MyHeritage along with his colleagues looked at the 1.2 million samples of DNA that had been submitted for sequencing. They could predict the genetic makeup of around 60 percent of the total population of European descent from the existing data. Relationships could be traced further using geneology records that are publicly available says Erlich. He called these “genetic geneology databases” as “GPS system for anonymous DNA.” He explained, “The family trees set a coordinate system, in which the DNA of each individual in these databases is like a beacon that illuminates hundreds of the individual’s relatives who are not in the database. Therefore, even if a specific individual is not in these databases, a relative of theirs could be, which is enough to identify them.”
Geneticist Shai Carmi of the Hebrew University of Jerusalem, who was part of this research said that genetic databases cover around 2 percent of the total population and “a match of a third cousin or closer is expected for almost all persons of interest.” The team wrote that in April 2018 over 15 million had undergone “undergone direct-to-consumer autosomal genetic tests” and this was a sizable population that ensured the rest could all be accounted for.
As a test of their theory the team tried to track a person down using the genetic and genealogical information along with public information such as age and address. They wrote, “We found that the suspect list can be pruned from basic demographic information. Our simulations indicate that localizing the target to within 100 miles will exclude 57 percent of the candidates on average.” A further pruning to 5 years age range and gender could exclude 90 percent of the possible matches leaving behind a handful (16 or 17) to be followed up. They add, “the technique could implicate nearly any U.S. individual of European descent in the near future.”
As of now adequate number of people of African and Asian descent have not registered on the public DNA databases and thus they cannot be analysed fully say the researchers.
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