One Twin Committed the Crime ? but Which One? A New DNA Test Can Finger the Culprit

New advances in DNA sequencing are making it possible to pinpoint those mutations — and to tell identical twins apart.This kind of test could well determine which of the brothers committed the rape. The court was forced to rely on other evidence — the timing of the woman’s pregnancy, for example — to decide that Raymon Miller was in fact the father.Faced with such cases, forensic DNA experts tried something once thought impossible: building a test that could tell twins apart. If a test could compare not just STRs but the entire genomes of twins, Dr. Krawczak and his colleagues wondered, could it tell them apart?In 2012, the researchers offered some calculations suggesting that the answer was yes.Imagine, they said, that a court heard a paternity dispute involving identical twins. Mr. Deakin got a court order for a new DNA test, hoping the McNair brothers were fraternal twins.“No such luck,” said Mr. Deakin.Try as they might, investigators couldn’t firmly determine which of the identical brothers had participated in the rapes. Mr. McNair was found guilty in January 2018 and sentenced to 16 years in prison.Since Eurofins published the initial test in 2014, only one other court has asked the company to test twins — in a civil paternity case in Germany, according to Burkhard Rolf, director of DNA forensic services at Eurofins.[Like the Science Times page on Facebook.