Connemara Genetics

In Connaught, almost all men (98.3%), carry a particular gene (haplogroup 1) that links them directly back to the ancient population of Ireland 4,200 years ago.  
10,000 years ago most of the population of Western Europe carried the haplogroup 1 gene.  Through the movement and mixing of peoples, this gene was diluted and today it is found in relatively few people in Europe.  
In 2007 Scientists in Trinity College studied the genes on the Y chromosome which is passed from father to son. By performing a number of genetic tests they were able to identify a particular genetic pattern in the Y chromosome of the Irish.   They estimated that most of the genetic variation in Ireland has accumulated over the past 4,200 years following a rapid growth of the population at this time. This is the time of the Early Bronze Age in Ireland.
The scientists have shown that most of the genes present in Ireland today came from the people who were living at the time of Newgrange. These people were the descendants of the ancient hunter-gatherers of Europe.
They also found a gradient from east to west in Europe. The lowest frequency of the gene is in Turkey and the highest frequency in Ireland where 78.1% of all men have the gene.
The most striking finding was that in Connaught, the western most point of Europe, almost all men (98.3%) carry this particular gene. This indicates a relative genetic isolation of the Connaught population over time.
The frequency of the gene varies according to the original source of the family name. For Gaelic surnames names the frequency is highest whilst Scottish surnamed people have the lowest frequency of the gene.