The genetic pool of the ancient male population in the Iberian Peninsula in Southwestern Europe was replaced by migrants from Central Europe thousands of years ago.
The ancient population of the Iberian region that is presently known as Spain, Portugal, Andorra, and Gibraltar was predominantly hunters and gatherers. They settled in mountainous areas and lived in what is considered a violent society. The social structure and genetic make-up of Iberians changed in the late Neolithic or Stone Age era.
The study of Iberian DNA led by the Institute of Evolutionary Biology focused on the genetic history of the Iberian peninsula and the movements of people across the globe.
Vanished Y Chromosomes
A large group of population geneticists and archaeologists sequenced 8,000 years of Iberian population history and studied the genome composition of more than 271 ancient individuals from Iberia who lived between 6,000 BC and 1,600 AD. They combined the data gathered with previously published information on 132 peninsula dwellers.
The researchers probed when and how different populations merged with the Iberians. It showed that 40 percent of Iberian ancestry and 100 percent of the paternal lineage in the study could be traced back to Central Europe. This means that the original Iberian male population left no genomic legacy or direct descendants today.
Among the most prominent ancestry that joined the Iberians were the "Russian Steppes."
As to what transpired with the original Iberian male genome and their Y chromosomes, which are passed from men to men, remain a mystery.
"The results were astonishing. The data suggest there was a major genetic change that is not obvious from the archaeological record," according to Carles Lalueza-Fox, co-senior study author and principal investigator of the Paleogenomics Lab at the Institute of Evolutionary Biology.
Migration Changed The Iberian Population
The study also uncovered that sporadic contacts between Iberia and North Africa happened between 2500 BC and 2000 BC.
After the Steppes ancestry replaced the ancient male Iberians, it further spread to Indo-European speaking regions. Greek and Roman settlements also appeared in Iberia.
The resulting multi-ethnic flow of people, the mixture of ancestries, and settlements in Iberia over thousands of years led to the transformation of the Iberian population. In fact, fossils from Iberian hunters-gatherers showed that the ancient population had more diversity than previously thought.
The study on the genomics of the Iberian Peninsula is published in the Science journal. A companion study is published in the journal Current Biology.