A long conversation about dna has been taking place over a couple of profiles I've been studying so perhaps this is time for me to ask the question that has been bothering me. Just what can be demonstrated by sampling the dna of living people? My understanding is this, we inherit our dna from our parents in a random manner. If neither of them has a particular gene then nor can we. Very, very occasionally a glitch happens and things can be changed, usually for the worse but sometimes for the better. In the past if it was useful more recipients would survive than otherwise, if unhelpful then fewer but this could depend on the environment. Some genes don't display physically unless you receive them from both parents, some are sex-linked (colour blindness for example). Third year biology, as far as I ever went. Statistically we inherit half from each parent but that's only statistics and statistics are only useful for studying populations, not individuals and it is possible though very very very rare to inherit all one's dna from just one parent. (That's like winning the lottery, almost impossible but people gamble anyway.) So if we test all the living members of a family we should be able to tell where they all fit in. But that's not so. Were my father also my grandfather (both dead) some say it would show in the statistics, but that is not necessarily the case. Surely all we can actually do with dna is demonstrate that the paper trail is probably wrong? Clearly I am a sceptic. I'm not entirely convinced that the remains recovered a few years ago are proven to have been Richard III, I'd bet there was a lot of unrecorded royal dna floating around then and there is now, though he did have an interesting skeleton. I have been told that it might be possible to determine who my unknown grandfather was by sampling my dna but I cannot believe it. In time it might be possible to say this guy is possible but there were probably a lot more possibilities around then. As I said earlier, statistics prove nothing much about individuals and from what I have read on here the analysis is mostly based on statistics determining cousins, etc. Wouldn't mind being enlightened.