Professor Sykes discusses tracing our genes back to our ancestors

Student:
Could you trace it all the way back to one male and one female?

Professor Sykes:
It's logically inevitable that every gene will eventually go back to one ancestor. And it's logically inevitable that the M-DNA ancestor would have been a woman. So we can trace it back to a woman by looking at how many mutations that happened since, and work out roughly 150 thousand years ago. We can do that with men as well.

The other genes we'll trace back to different ancestors and we don't, we're not going to know if those are men or women, and it's actually quite hard to know as well. For many different reasons it's really hard to know how long ago they all lived, but ultimately (theoretically) you could do it with all of our genes.

Now, interestingly enough, not all of those common ancestors would actually have been human. Because we have genes, for example some of our genes that are concerned with blood groups and other things, are so old that the common ancestor is pre-human.

Pre-human would be somewhere along the line between our common ancestor, the human common ancestor and our closest living relatives which, of course, are the great apes - the gorillas, the chimpanzees, orang-utans and so on. If you follow Darwin's ideas about evolution, because often people don't follow those, but if you do then that's the case that we have many genes whose common ancestors of all of us were pre-human.