Did you know that our ancestors could have changed the very genetic material in their descendants by crossing a mountain range!
This is exactly what researchers recently discovered as they studied the migration patterns and fossilized remains of people from the Bronze Age (beginning in 2500 BC) who navigated over the Pyrenees Mountains to live on the Iberian Peninsula. The Iberian Peninsula is located on the modern-day continent of Europe and is home to the countries of Spain, Portugal, and Andorra.
Researchers extracted DNA from many Bronze Age Iberians and found that many of them traced their ancestry to the few Neolithic farmers (people from the Stone Age) living in various places in Europe including Spain, while the rest of their genetic makeup was similar to people who lived on the Russian Steppe (grassland plains between Europe and Asia.
The analysis of these historical footprints aimed to uncover the full history of the widespread migration and better understand the evolution of humanity since the Neolithic Age.
What Caused the Pyrenees Crossing?
One scientific theory to explain the Pyrenees Crossing is the emergence of an ancient plague in Sweden. Scientists support this theory with the fact that Y. Pestis, a bacteria that causes the pneumonic, septicemic, and bubonic plagues, spread during the end of the Neolithic Age.
By comparing the genomes of Iberians and other early humans to analyze the presence of diseases in them, scientists concluded that an epidemic possibly sprung up in large establishments near the steppes and over trade routes.
Researchers also analyzed the presence of the Y chromosome, a spool of DNA that is typically passed down unchanged from father to son (in a paternal line). After analyzing the DNA data, scientists discovered that the original Y chromosome lineage disappeared from the local Iberians’ genome before the arrival of the new migrants and was replaced with a Y chromosome that matched that of the migrants!
What Does the Research Tell Us?
Male domination was a key aspect of the migrants’ society, especially given the replacement of the original Iberians’ Y chromosome. Iñigo Olalde, a co-author of the genetic study report, said that “It would be a mistake to jump to the conclusion that Iberian men were killed or forcibly displaced,” because there was no evidence of violence in the archaeological record.
In fact, the theory is that early clans were structured in such a way that only the first-born son inherited the clan’s property, while the rest of the sons would establish new clans elsewhere to spread their male lineage.
Scientists also concluded that the people of the steppes moved west and integrated elements of other cultures into their own.
DNA can tell us so many incredible things about our past, and this is just one of them. Even after so much exploration, much of the long history of humanity remains unknown. Researchers continue to make more and more discoveries and one day, all of these discoveries may finally unlock a key to our past.
Sources: National Geographic, BBC, New York Times, archaeology.org