How shellfish saved the human race

Cool article posted on boingboing:

http://www.boingboing.net/2009/12/16/how-shellfish-saved.html

A couple hundred thousand years ago, the planet became a much colder and drier place. In Africa, deserts expanded, species were wiped out and the human race was in deep trouble.

See, humans today may look pretty different from one another but, genetically speaking, there's not much diversity at all within our species. In fact, chimpanzees, which look pretty much the same from one individual to the next, are much more genetically diverse than we are. To scientists, that suggests that humans have come through a genetic bottleneck--a point where our numbers shrunk dramatically, and a relatively small population had to rebuild the species. For about 20 years, genetic anthropologists have been comparing the genes of modern human populations. Over time, they've used bigger and bigger samples, and better and better analysis, to hone in on when our bottleneck likely happened, and how many humans managed to slip through it.

Turns out, somewhere between 130,000 to 190,000 years ago, the human species was reduced to less than 1000 breeding individuals--just a few thousand people in total. Ancient, naturally driven climate change pushed our species to the brink, said Curtis Marean, Ph.D., a professor with the Institute of Human Origins and the School of Human Evolution and Social Change at Arizona State University.

What saved us? According to Marean, the answer may be "shellfish".

more at the link