Humanity's Genetic Footsteps.
With the science of genetics it is possible to work out a sort of family tree. If, for instance, two populations labeled "A" and "B" have more neutral mutations (mutations that do not alter the function of a gene) in common than a third group "C" it is most likely that peoples "A" and "B" were interbreeding after they lost contact with group "C". When you combine this information with information about current genetic distribution and known history and prehistoric archaeological evidence, you can put together a fairly good picture of how human migration has played out in the long expanses of time.
That is what this project is doing and not a moment too soon.
I should mention to anyone who believes in common decent for humans (Adam) but not for humanity (hominids) that the first sentence in the article does not offer the rock solid proof of this view point that it may seems:
" New DNA studies suggest that all humans descended from a single African ancestor who lived some 60,000 years ago."
Any person who lived long enough ago and had a large number of grandchildren can make this claim because their descendants will eventually become so numerous that they will mate with everyone else's descendants. It is simply that 6o,000 years is as far back as this method would allow us to trace connections. I don't understand why the National Geographic would not see that this phrase could be misinterpreted.
I say that this is happening "not a moment too soon" because the genetic history is starting to fade. Throughout human history people have traveled, both as groups on the move and as individuals between groups and genes have constantly spread between populations. This has been on such a small scale that large migrations, and merging and splitting of populations are still determinable in the current genetic distribution of humanity. In the last few centuries however, with the modern age of exploration, expansion, colonization, migration, slave trading and tourism, there has been a tendency for widely distributed peoples to come in contact with each other. Now from a medical/genetic-wellbeing point of view this is great. When formerly isolated populations begin to interbreed they can both draw on a larger population of potential mates and far more genetic combinations are possible. Also, genes which are dangerous when inherited twice are diluted in frequency so the chance of anyone getting one from each parent is reduced. From a genetic-genealogy point of view however it means that the clock is ticking. As populations interbreed the difficulty in accumulating the information increases and the geographic context is lost.
This project had been proposed earlier for a different purpose. The Human Diversity Project was going to sample genetic information from all over the world just in case there were medically useful gene versions (alleles) that could provide cures or treatments. As unlikely as this was due to the fact that human populations are not very diverse at the level of the actual protein coding genes, it was enough to worry indigenous groups and others about biotech companies pirating genes from poor people and not reimbursing them; perhaps even charging them to use the medicines that came from their kinsmen's genes.
This time there is a more realistic goal (scientific information rather than "possible" cures) and there are safeguards to prevent exploitation. Having gathered the genealogical information available in our cells we can keep mixing our genes willie-nillie without worrying.
While I am not sure if it was officially part of this project, I seem to remember there being another National Geographic article about using genetic samples from existing populations to shed light on history. They traced the regions of contact of the ancient Phoenician sailors of the Mediterranean and found that not only were the Muslims of coastal Jordan direct descendants as they had always claimed but the Christians there were also (obvious in hindsight but no one ever thought about it) While it might be naive to think that this revelation of common history would have all that profound an effect on these communities as they come together after the civil strife of the past, every little bit helps. This research also showed that the Phoenicians had settlements quite far up the Atlantic coast of Europe which lends credibility to archaeological evidence and theories of contact there.
I also recall two different groups, one in southern Africa and one in India who were found to have customs that were similar to old tribal Jewish traditions. Genetic evidence seems to have confirmed the link if I remember the stories correctly.
Unfortunately for some, the evidence is not always what some people would want to hear. While the Mormon authorities have mostly accepted that the DNA evidence does not support their claims about Native Americans being of one of the lost tribes of Israel, this information is not widely publicized to their members.
This new tool of comparative genetic analysis will be very useful to disciplines such as history, anthropology and archeology. The more tools and techniques we can use to examine the past, the clearer our picture of it becomes.