Howdy all
Watching a rerun of Monster quest last night a question popped into my mind.
If a stool sample is taken and the animal had eaten another animal would the eaten animals DNA show up in the results ?
The reason I am wondering is they tested some stool and it came back a known animal. But they said while it was being tested it was "Cleaned up" in other words anything that did not fit a known DNA sample was taken out.
So any of you smart people out there can you help on this question ? Would a animals DNA show up in another animals stool after being eaten ?

good question!

I doubt DNA from consumed animals tissue would, unless sealed within in some bone fragment or tooth protected by the enamel or some kind of undigestible hull,or hair (good chance some of that could maybe). Plant DNA in seed and spores routinely does because of that and there are all kinds of living organism within the exrected product...but the enzymes and biochemical processes are pretty thorough if the digestion is workin on properly chewed up food, I think you could imagine that if the system evacuated itself prematurely via diarhea, some tissue wouldn't have had time to be reduced...but one thing that does survive is a trace of myoglobin wich is a component in animal blood, that can be detected in feces. A recent example was that some feces found in a long sealed chamber in which was evidence to suggest that cannibalism thought to have occured. The stool, while dessicated still contained traces of this myoglobin and it was specific to humans if I recall the article correctly. I presume that means that different species might have different specific types of myoglobin. Ergo; one can examine a stool sample and determine something about the species of animal flesh consumed after being processed and deposited. Might be a wiki on that somewhere, though I heard there was some sensitivity about the interpretation of that specific archeo site.