Character mistake: McCoy asks his witness, an expert geneticist, what the odds are that a DNA sample presented in evidence does not match that of the defendant. He answers "About one in two hundred." That is idiotic. If the DNA samples are identical the chances that the the sample presented in evidence does not come from the defendant is about one in two billion, not one in two hundred! A bright high school senior would know that, never mind an expert geneticist.
Suggested correction: If the odds are 1 in 200, that means the accuracy of the DNA is 99.5%. If the odds are 1 in 2 billion, that means the accuracy of the DNA is 99.9999999995%, which simply isn't true.
In fact as any geneticist (i.e, anyone like me) will tell you the chances of two identical DNA "fingerprints" coming from two different and unrelated individuals are around one in two thousand million. Two billion. In fact the odds are much higher than that but we scientists don't like to make claims that sound unlikely or fantastic. The accuracy of DNA fingerprinting is, as you point out, 99.9999999995%. You correction is wrong and the posting is correct.
Except that's not what happened in the scene or what happens in real life. You simply don't understand what you're arguing. You're not a geneticist.
