The First Humans in Belize
Since the first stone arrowheads were discovered in Clovis, New Mexico in the 1920s, archeologists have been working to understand how early humans first came to the Americas. A new DNA study that compared modern genomic information to that recovered in several ancient sites across the Americas has now revealed that human beings entered Belize in several separate migrations.
Scientists have long known that ancient humans crossed a land bridge from what is now Siberia into northwestern Canada some 16,000 years ago. But by comparing ancient DNA with different modern population groups, scientists have learned that there were actually two different groups which reached America from Asia. The ancient Beringians separated from another group about 20,000 years ago but subsequently disappeared, leaving no known trace in the genome of modern people. Therefore, it was actually the second wave of immigrants which kept pushing south until they reached Belize some 14,000 years ago.
Archeologists also used to believe that it took several thousand years for humans to make their way south into Central and South America, but new techniques for studying ancient DNA has rocked the scientific world by proving that it took only a few hundred years at most for humans to reach the tropics of Belize. Previously, a lack of fossil records made it hard to determine the exact speed at which humans spread out across the Americas, but by analyzing the genomic information of modern indigenous people, scientists now know that emigration southward occurred relatively quickly.
A team from Harvard University has recently developed new techniques for recovering DNA from ancient samples, allowing for a more comprehensive comparison between DNA from ancient humans in the Americas and modern inhabitants. Scientists can now show that the Americas were populated by waves of different peoples rather than the slow diffusion of a single culture. In Belize, for instance, about 9,000 years ago, a small existing population was replaced by a third group of immigrants coming south from North America. And it is this wave of humans who later formed the nucleus of the indigenous peoples found from Brazil all the way to the southern tip of Chile and Argentina.