DNA testing to distinguish identical twins

As reported in the American Bar Association Journal, Prosecutors in Boston say a new DNA test offers proof that they have charged the correct identical twin in the rapes and robberies of two women in 2004.  It was reported in the New York Times that the suspect pleaded not guilty on to eight counts of aggravated rape and two counts of armed robbery.  The Defendant was arraigned after the test by a company called Eurofins Scientific concluded he was 2 billion times more likely to have been the source of the DNA evidence than his identical twin brother.   In a statement, Suffolk County District Attorney Daniel Conley said the scientific foundation for the test technique is well-established, though its forensic application is new. “To the best of our knowledge our case will be the first prosecution to use it.”

In a recent press release, Eurofins describes its “research breakthrough” proving that rare genetic mutations can occur soon after or before the ovum splits in two, the process that produces identical twins. Such mutations are carried into body and sperm cells.  University of California at Los Angeles law professor Jennifer Mnookin told the New York Times that she has not heard of any U.S. case using the test. A judge will have to consider whether the test can be admitted as evidence. “They should make sure the tests are ready for prime time,” she said.

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