Hi Janet! As far as I know genealogy DNA test samples do NOT come from dead people. As I understand it if you start a group the first person to give his DNA sample has to have a proven paper trail back to his Earliest Known Ancestor(EKA).Then other men with the same surname submit their DNA sample. Then the lab gives you the results & tells you if you are related to the original person or not. I hope this explanation is not as clear as mud. DNA tests are just another tool in helping you find your ancestors in my opinion.I'm happy with this method myself! Pam in IN.