The truth about DNA
DNA is considered the gold standard in forensic science; and recent reports highlighting some of the failings in other forensic disciplines, such as fingerprints and bite-mark analysis, have only confirmed DNA analysis as the way forensic science should be practised.
Mock trials show that jurors are more likely to convict when presented with DNA evidence than with other kinds of evidence. And DNA profiling is generally viewed as objective, reliable and scientific. But is it infallible? And if not, could the growing reliance on DNA analysis trigger the same sort of miscarriages of justice that have clouded the reputations of other forensic disciplines?
Linda Geddes has investigated whether the interpretation of DNA profiles is truly objective, or whether subjectivity and bias could be an issue in certain cases. Although the potential for subjectivity in DNA analysis has been raised by defence lawyers and several prominent academics in recent years, this is the first attempt to actually quantify it in any formal way.
By demonstrating that DNA interpretation is subjective, she has shown that the difference between prison and freedom could rest on the opinions of a single individual. Her investigation has profound implications for criminal justice worldwide.