Over the decades, there have been many theories as to where the first people to get to the
New World originated, and now, thanks to DNA, we likely have a definitive answer.
We humans have a couple million years behind us, and it's taken us nearly that entire time
to spread across the planet. Anthropologists know for a fact humans evolved in what is
now Ethiopia and Somalia. Eventually modern humans stood up and started walking out of
Africa, but not long afterward, things get a bit blurry.
By following the fossil record, humans moved from Eastern Africa into South Africa and
onto the Arabian Peninsula. Over thousands of years, modern Homo Sapiens migrated throughout
Europe and Asia, supplanting or interbreeding with populations of Neanderthals and Homo
erectus. Eventually, modern humans spread to the New World and populated there too,
but how humans made it over here -- when the map makes it look SO. FAR. has been a puzzle
with many hypotheses, until DNA was discovered.
Before DNA, scientists looked at fossils and traits and the geologic record and theorized
humans moved onto a land bridge which existed between Asia and North America. The Bering
Land Bridge probably conjures pictures of, well, a tiny little bridge. But it's a bridge
like France is a bridge from Spain to Germany; it's also called the Bering Plain. The land
bridge was a massive amount of land connecting the two continents. People moved ONTO the
bridge 23,000 years ago, and then moved OFF the bridge maybe 15,000 years ago…
Now, new science has confirmed most of the Bering Land Bridge theory, and added even
more specifics as to how First Peoples or Native Americans found their way onto this
continent. A new paper in Science sequenced the genomes of 23 ancient individuals and
31 living Native peoples and found a very specific genetic history. DNA carries with
it a step-by-step record of interbreeding and adaptations in its billions of quad-coded
nucleobases. Since the human genome was completely sequenced in 2003, we don't know what everything
in there does, but we do have a baseline.
Here's what happened, no more than 23,000 years ago, Amerindians (as they called them)
moved from Siberia in a single wave and settled in the north for thousands of years. From
there they split into two groups about 13,000 years ago. We know that the glaciers were
receding about then. That meant the land bridge was shrinking. One group settled throughout
North America and while the other settled in Central and South America! Incredibly,
they pinpointed the 13,000 year split figure, based on the DNA from the remains of a single
12,600-year-old boy. As they sequence more ancient individuals they'll get even more
precise migration estimates.
But that's not all, they also answered the long-wondered question, where did the Natives
originate? According to the genetic information, Native Americans have a small mix of genes
from East Asians and Australo-Melanesians. Australoid and Melanesians are two racial
classifications which include Southeast Asian hunter-gatherers, Papua New Guineans, Solomon
Islanders, Vanuatuans and Indigenous Australians! Somehow, people from as far away as remote
islands in the South Pacific and Australia were able to make their way to the New World.
It's mind-boggling to think of ancient people migrating so far and mixing with the locals.
Today, more than 80-percent of our planet has seen influence from human activity. Studies
like this show us just how little we know about how we got here; and how much of an
impact we've made in such a short time on our Earth..
Do you have a curiosity we can quench?
For a FULL recounting of how we all got where we are now, check out my new show TestTubePlus
We spent 5 episodes in a series on humanity and where it came from.