Ireland is one of the last great repository for a group of genes that were common across Europe and which date back to pre-Neolithic times, before humankind had developed agriculture. The only other place where these ancient genes are conserved to such a degree is the Basque country.
A research team from the department of genetics at Trinity College set out to create a new genetic map of Ireland, and to compare this with existing gene maps of Continental populations. The team suggests that a common genetic marker was established in males here at least 6,200 years ago, long before the English, Scots or Norman invasions and before the Celts.
Dr Dan Bradley and Dr Emmie Hill present details of their DNA study this morning in the science journal, Nature. The research supports the theory that "on the edge" populations in Europe managed to avoid the genetic changes driven by the evolving demographic picture caused by invasions, plagues and migration, Dr Bradley said.
They tested DNA from 221 individuals here, looking for 13 genetic markers in Y chromosomes - genes that are passed on from father to son. Most unusually, they also grouped subjects on the basis of family names, choosing a mix of Irish, Scots, English, Norman and Norse. "Surnames are a real indication of ancient paternal origins," Dr Bradley explained.
The ancient genetic markers tested for are known as haplogroup 1 (hg1). It is believed that most of western Europe's population 10,000 years ago carried the hg1 marker. This population was diluted over generations by migrants moving westward after the discovery of farming, thus producing a hg1 "gradient".
This gradient reaches its maximum value in Connacht, Dr Bradley found, with the hg1 marker detected in 98.3 per cent of those tested. It falls to 50 per cent in France, about 33 per cent in northern Italy, and to just 1.8 per cent in Turkey, but rises to 89 per cent in the Basque country.
"The west is almost entirely haplogroup 1, but there was a significant amount of mixing in the east," Dr Bradley said. Leinster is 73.3 per cent hg1, Ulster 81.1 per cent and Munster 94.6 per cent.
He estimated that the hg1 markers were established here about 6,200 years ago, long before the Celts brought their spiral art and pagan ways. "Our evidence is not consistent for the bulk of Irish people with an Iron Age invasion that made Irish DNA what it is today," he added.
Despite the relatively small sample size, the team saw an immediate statistical association between presence of hg1 and surname. "Surnames are a real indication of ancient paternal origins," Dr Bradley explained.
Those with native Irish names were much more likely to have the hg1 marker than Irish people having surnames with connections abroad.
