Boffins at Trinity have done something amazing. They have sequenced ancient Irish DNA. Who we thought we were, isn’t exactly right. There’s more to the story than originally thought.
We Irish kinda hoped we’d always been here on this emerald isle. But actually, we migrated here like everyone else. The genomes show unequivocal evidence for mass migrations into Ireland. These genetic influxes are likely to have brought cultural changes including the transition to agriculture, Bronze metalworking and may have been the origin of western Celtic language. Yes, that language we are forced to learn in school…? It wasn’t always here, it was dragged by migrants to our rainy shores.
So how do we know this? Because a team of geneticists from Trinity College Dublin and archaeologists from Queen’s University Belfast have sequenced the first genomes from ancient Irish humans. Having cracked this chestnut open, they have discovered information answering pivotal questions about the origins of Ireland’s people and their culture.
The team sequenced the genome of an early farmer woman, who lived near Belfast some 5,200 years ago, and those of three men from a later period, around 4,000 years ago in the Bronze Age, after the introduction of metalworking. Their landmark results are published in the international journal Proceedings of the National Academy of Sciences, USA.
So what did they find out? Ireland has intriguing genetics. (But we knew that.) Ireland lies at the edge of many European genetic gradients. But our genes are peculiar in that we are awesome at being ultra lactose tolerant. Bring on that ice-cream! But we have some bad stuff too. Genetic diseases including one of excessive iron retention, called haemochromatosis, stalk us. So we can digest milk easily but we have problems with iron. Sounds like a fair trade, almost.
We know all this, and yet, the origins of this heritage are unknown. Migration has been a hot topic in archaeology. Opinion has been divided on whether the great transitions in the British Isles, from a hunter-gatherer lifestyle to one based on agriculture and later from stone to metal use, were due to local adoption of new ways or whether these influences were derived from influxes of new people.
These ancient Irish genomes each show unequivocal evidence for massive migration. The early farmer has a majority ancestry originating ultimately in the Middle East, where agriculture was invented. The Bronze Age genomes are different again with about a third of their ancestry coming from ancient sources in the Pontic Steppe (the vast steppeland stretching from the northern shores of the Black Sea, from Moldova and western Ukraine, across Russia to western Kazakhstan).
“There was a great wave of genome change that swept into Europe from above the Black Sea into Bronze Age Europe and we now know it washed all the way to the shores of its most westerly island,” said Professor of Population Genetics in Trinity College Dublin, Dan Bradley, who led the study. “This degree of genetic change invites the possibility of other associated changes, perhaps even the introduction of language ancestral to western Celtic tongues.”
“It is clear that this project has demonstrated what a powerful tool ancient DNA analysis can provide in answering questions which have long perplexed academics regarding the origins of the Irish,” said Dr Eileen Murphy, Senior Lecturer in Osteoarchaeology at Queen’s University Belfast.
Whereas the early farmer had black hair, brown eyes and more resembled southern Europeans, the genetic variants circulating in the three Bronze Age men from Rathlin Island had the most common Irish Y chromosome type, blue eye alleles and the most important variant for the genetic disease, haemochromatosis.
The latter C282Y mutation is so frequent in people of Irish descent that it is sometimes referred to as a Celtic disease. This discovery therefore marks the first identification of an important disease variant in prehistory.
“Genetic affinity is strongest between the Bronze Age genomes and modern Irish, Scottish and Welsh, suggesting establishment of central attributes of the insular Celtic genome some 4,000 years ago,” added PhD Researcher in Genetics at Trinity, Lara Cassidy.
We seem to be a strange mix of many types of genes, and it all adds up to a whole lot of Celtic awesome. Bring on that ice cream cone.