Problem:
I have read that a chimera is an organism with two or more sets of DNA, with every cell having one of the sets. Is it possible and common for the two or more sets to be present in the cells of a single organ? I'm confining my question to vertebrates because I don't remember much about the biology of invertebrates from high school, but please don't hesitate to add anything interesting about them.
Please provide some description about it.