Nothing technical today, sorry
Went to a fascinating lecture last night with friends of the family (the Bowras). It was a part of National Geographic’s “National Geographic Live!” series. The NG Live series is a series of three or four lectures given every spring that presents National Geographic lecturers presenting information about stuff on which the society is working. The Bowra’s have invited me to come along with them to a couple of the previous lectures in the series, the one with Robert Ballard (as in the guy who found the Titanic) was especially fascinating.
Last night’s lecture was Spencer Wells presenting the materiel in his book (and NatGio special) Tracing the Journey of Man.
It was a fascinating lecture. Spencer Well’s is one of the people who did the research that determined that all humans descend from a pool of approximately 2000 individuals who lived in Africa sometime about 60,000 years ago.
He figured this out by measuring the amount of genetic variation in human beings – what I hadn’t realized is that humans are very different from other primates – the genetic diversity in most primates is around 25%, while humans have only a two or three percent genetic diversity. The only way that they could explain this is that there had to have been a tiny pool of original ancestors for all humans alive on the earth.
By tracing genetic markers that live on the Y chromosome, his team was also able to determine that human beings actually spread from two different locations – one in Africa, the other, about a thousand or so years later from Australia. His team figured that about 60,000 a group of people left Africa and followed the coastline across the Indian subcontinent and then crossed a land bridge into Australia. From there, humans spread out from both population centers to cover the world (that took about 15,000 years).
One of the things I loved was how he figured this spread out. He couldn’t find any oral tradition of a great journey in the tales of the Australian Aborigines, so he figured that if they HAD made the journey, he’d be able to find genetic markers along the route.
And in fact, when he went to India and started sampling the population, he discovered a genetic marker that the people he sampled shared in common with the Aborigines. And that marker dated from somewhere about 55,000 years ago.
So he deduced a testable theory from his hypothesis, then performed the experiment and confirmed it. Very, very cool.
My favorite moment was during the Q&A question when someone asked: “Have you had any resistance from local authorities to your research? And can you present it in Kansas?”. That got a HUGE round of applause.
My biggest complaint about it was that the last 1/3 of the lecture was essentially a sales pitch for NatGio’s new Genographic Project.