• A new method for solving forensic genetic puzzles is ten times faster than the current method investigators use to solve crimes.
• Researchers from Stanford and genetic organizations have developed a decision-making algorithm that uses probability to narrow down which areas of a family tree to focus on—which are often extensive and go back hundreds of years—to more efficiently identify the DNA target.
• The Golden State Killer investigation, which investigators finally solved in 2018, popularized forensic genetic genealogy.

Scientists say using math to sort through DNA could help investigators put stubborn cold cases to rest. The approach combines the relatively new field of forensic genetic genealogy—solving crime by charting out DNA-based family trees—with increasing computational power to speed up and simplify this complex form of investigation.

In a new paper recently published in the Journal of Forensic Sciences, researchers from Stanford University, California-based Identifinders, and the DNA Doe Project explain how they developed a new mathematical model to help investigators greatly narrow down their giant pools of genetic candidates:

“We formulate a program that—given the list of matches and their genetic distances to the unknown target—chooses the best decision at each point in time: which match to investigate, which set of potential most recent common ancestors to descend from, or whether to terminate the investigation.”

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