Prehistoric Irish people were dark skinned and had blue eyes, a new documentary claims.
The hunter gather population that lived in Ireland 10,000 years ago do not have any of the pigmentation profiles associated with light skin.
They inhabited the island for 4,000 years before being replaced by settled farmers.
The information is contained in a documentary about the Burren in Co Clare broadcast on RTÉ on Sunday.
According to TCD geneticist Dr Lara Cassidy, techniques normally used in forensic criminal investigations have revealed surprising details about prehistoric Irish people.
Scientists have been developing a genetic database of ancient Irish genomes from all periods of pre-history to understand how the modern Irish gene pool came about.
She said the hunter-gatherer Irish not only had dark skin, but also bright blue eyes – a combination rarely seen today.
They operated mostly along the coast of the Burren gathering shellfish, and then moving inland to hunt wild boar and gather hazelnuts.
The Burren’s unique geological landscape means it has preserved evidence of millennia of settlement in the area of west Clare.
The hunter gathers were replaced by early farmers. The earliest evidence of farmers in Ireland is in the Burren. They arrived approximately 6,000 years ago in what was known as the Neolithic era.
"We know now from ancient genomes that farming was accompanied by a whole group of people moving into the continent from the region now known as modern Turkey, " she said.
They brought cattle, sheep and goats, pottery and new housing structures. They have lighter skin than the hunter gather, but more sallow than today.
“There could have been violence. This would have been quite a dramatic colonisation event,” Dr Cassidy added.
However, it is more likely that they co-existed peacefully as the remains of one early farmer showed that he had hunter gatherer ancestry.
Gene pool
The early farmers began by clearing the trees with polished stone axes to make for arable land. They built the dolmens which populate the area.
In 4,000 years the last wave of early settlers came to Ireland. They were at the tail end of a large scale migration in the Steppe region of Russia into western Europe.
“Only at that point do we see the establishment of the modern Irish gene pool as we know it today,” Dr Cassidy added.
Environmental biologist Carl Wright said the Burren once featured high mountains with a thick forest covering. The mountains were replaced by glaciers during the Ice Age which removed a kilometre of rock off the top of this landscape.
The early farmers relentlessly cleared the forests until there was hardly any of the original forest left.
“They overgrazed the Burren during the climatic downturn of 3,000 years ago – this led to an environmental disaster on a colossal scale, because over a very short space of time we have massive soil erosion which pretty much left us with the landscape that we have at the end of the last ice age. Literally just bare rock, the soil was washed away,” he said.
The Burren: Heart of Stone, directed by Katrina Costello, is now available to view on the RTÉ Player
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