DNA evidence may have been misleading to courts

Abstract

Courts are being misled about the strength of evidence based on DNA, according to two mathematicians writing in last week's issue of Nature. David Balding and Peter Donnelly, of Queen Mary and Westfield College, London, argue that the adversarial nature of the British legal system and the “siege mentality” of some forensic scientists have often led to evidence being presented in a partisan and misleading way. The article points out a common “prosecutor's fallacy” when the probability of guilt is assessed in the light of a possible match between samples of DNA. The strength of a correlation between the DNA of the accused and the DNA of the crime sample is expressed by …