Humans evolved in Africa, then started heading north and once they hit the Middle East, we quickly spread into Asia and Europe. That has been pretty well documented, decided, and agreed on by anyone who, you know, studies facts for a living.
The question of how, when, and in what sort of numbers humans made it to the Americas is still up for some level of debate. Most think they made it over a land bridge that once connected modern day Alaska and northeastern Russia. Sarah Palin had that thing taken down, though.
A lot of evidence comes from archaeological digs, most famously the Clovis sites, which for a long time were considered the earliest traces of human activity in the Americas, until other digs and finds challenged this theory and more or less put it to sleep.
What is generally agreed on, though, is that the people who first made it to North America, more closely resembled Mongolian, Chinese, and other East Asian peoples. How do they know this? Well, Indiana Jones has traded in his whip and satchel for a microscope and a copy of the sequenced Human Genome and through genetic analysis of human remains, and now scientists are using the sequenced human genome — the genetic blueprint for humans — to trace the migration of humans by figuring out how far groups of people wandered before screwing and later dying.
The lastest find, the 24,000-year-old body of a young boy found in Siberia, adds to the story, and mystery, of how and when people made it to the Americas. From the BBC:
“When we sequenced this genome, something strange appeared,” [researcher Eske Willerslev] explained. “Parts of the genome you find today in western Eurasians, other parts of the genome you find today in Native Americans – and are unique today to Native Americans.”
DNA from the boy’s Y chromosome and from the mitochondria (the cell’s batteries) were of types found today in a region encompassing Europe, West and South Asia and North Africa, but rare or absent in Central Asia, East Asia and the Americas.
The researchers estimate that 14-38% of the ancestry of Native Americans traces to a population like the one living at Mal’ta 24,000 years ago.
But the most puzzling part of this finding was that the boy showed no clear affinities with East Asian populations such as the Chinese, Koreans or Japanese.
Today’s Native Americans are most closely related to East Asians, so the scientists had to work out how the Mal’ta boy could be related to indigenous Americans, but not to East Asians.
The most likely scenario, they argue, is that a population like the one living in Siberia 24,000 years ago mixed with the ancestors of East Asians at some point after the boy died.”
Unfortunately, until we learn how to speak to the dead about anything other than how jealous they are of our fancy modern medicine (I swear, that is ALL THEY WANT TO TALK ABOUT WITH ME!) we won’t be able to ask him what in god’s name his genetic material is doing in Native American genes.
Read more at the BBC.
photo credit: CGP Grey, Creative Commons/flickr