The mystery to me is why DNA wouldn't be identifiable after cooking. Can't we identify human DNA after a fire... as opposed to, say, another animal? Perhaps I've seen too many crime shows.
Any experts want to weigh in?
I'm no expert but I would posit that in the case of gathering DNA from a burn victim the DNA would be gathered from deep within the body, possibly from bone marrow even, where the temperature may not have risen much.