Student:
How does rain affect the DNA samples at a crime scene?
Robin:
It wouldn't affect it right away, but if it got wet and then maybe five days went by the DNA would be a little damaged. And if five months went by then it would be more damaged. So the time that a sample would be wet and outside would gradually damage the DNA over time, but cases have been done that are as old as twenty or thirty years old and that's not really all that unusual.
Andy:
We've done cases where we've recovered things like cigarette butts from toilets, so people have thrown cigarette butts down the toilet. We've recovered those and we've got DNA profiles from those. So you could immerse a sample completely in water and you'll still get the right profile.
Robin:
You can put it through the washer and still get a good profile.
