I am so thoroughly unknowlegable in technical science, I doubt I can even ask a valid question.
But, I’m gonna try anyway. How can there be any confidence that the DNA found on the chewed cud is from the cud chewer? The caves have been in existence since the cud was chewed, so it seems safe to assume that others have been in and out of the caves over the many centuries. How do they separate DNA unique to the chewer from all the possible/potential/probable contamination?
I do realize that in such issues, there’s a different level of pristine than what would be required for legal or criminal trial purposes.
I’m not trying to refute or poopoo the development, just trying to get up to speed in the how’s and whatfors.
PS. I’m pretty sure I wont be able to understand any answers but... maybe I can gleen enough hints on where to start reading up.
I can’t think of a way that human DNA would get into a cud, other than by chewing. If you were to pick one up, and rub it on your skin, some skin cells would slough off, and adhere to the surface, but the probably would not permeate the interior.