In an earlier post to this Blog I mentioned a National Geographic channel presentation of a show titled The Human Family Tree. I hope you had a chance to see it because it was a very clear explanation about how DNA can be used to show general relationships, and it was a revealing view of how closely related we all are. That last was shown very dramatically in the last quarter of the show. The program is being aired several more times, and I recommend you check your guide for show times.
But in case you are interested and can't see the show or your TIVO is on the blink, visit the NatGeo website and see some articles and videos about the topic. You can check them out at: http://tinyurl.com/nemop9