Europeans were already different from the Americas long before Columbus

Scientists used lab-based tests to show that Europeans’ genetic code is almost wholly useless when it comes to distinguishing between ancient North and South America, suggesting the region may have existed long before Europeans…

Europeans were already different from the Americas long before Columbus

Scientists used lab-based tests to show that Europeans’ genetic code is almost wholly useless when it comes to distinguishing between ancient North and South America, suggesting the region may have existed long before Europeans appeared. In the meantime, southern Americans, particularly Afro-Puerto Ricans, may be much more distinct genetically from other Latinos than anyone realized.

The key to deciphering the modern DNA of the various peoples of South America is called non-coding DNA, where specific genes don’t code for proteins that help humans make food, reproduce and grow. These genes don’t let us live as microbes or bats, but they’re also not connected to the expression of anything we do know: That is, our brains, hearts, lungs, skin and nervous systems are all powered by our DNA. As a result, people who lived for centuries without modern media of DNA can contribute very little.

Almost all DNA present in the human genome is in the non-coding areas, so researchers try to infer commonalities across large populations by analyzing the genomes of different groups within a nation and seeing how common the genes are. The way an SNP (single nucleotide polymorphism, in the genetic parlance) occurs in our DNA usually helps determine similarities with individuals or the species as a whole.

So how do the genes in the modern genomes of Afro-Puerto Ricans and southern Europeans look? In some cases, the clusters of SNPs identified in the South American population are basically identical to those found in the modern populations of Europe, so the use of existing SNP analysis is not enough to get past the genetic divide, according to Junghyun Jang, a research scientist at the San Diego Supercomputer Center.

But in other cases, genetic differences between southern Europeans and Latinos from Europe can be hard to explain. Jang and colleagues developed new algorithms that are compatible with the DNA from southern Europeans but that combine those with the DNA from Spanish-speaking South Americans. Even here, about 100 of the 400 SNPs that the researchers searched for appeared.

“If we had nothing to compare our results to, then it would be very tough,” Jang told The Washington Post. “But with a clue, I could propose that we think this could be South America.” He added that other SNP studies showing similar association are also relatively recent, “but we were ahead of them in scanning the entire genome of modern European peoples.”

All told, Jang and his colleagues found evidence of DNA signatures associated with Spanish-speaking populations but no definitive examples of the Spanish population. “In the end, it’s going to be very tough to prove that we’re not actually talking about an entire continent,” Jang said.

Deeper down, as yet undiscovered SNPs — some of which have found their way into Europe and Africa in recent years — may also have contributed to a greater extent to a historical divide between Europe and the Americas. The Africans of early modern Europe are part of those populations whose DNA has drifted toward South America.

“I think our current theory about people of South America and Europe is still being tested,” Jang said. “There’s still genetic evidence that, after seven centuries, the genetic line between the Americas and Europe still doesn’t cross.”

Leave a Comment