Northern Ireland is a land of two tribes - and it looks like that split is encoded in our very genes.
A new DNA study has revealed that genetically there is no distinct group of Celtic people spreading from Cornwall through Wales and into Ireland. But it has found that people in Northern Ireland are divided into two tribes - and both of them spread across the Irish Sea into Scotland.
The study, published in the journal Nature, examines a detailed DNA analysis of 2,000 Caucasian people living across the UK, all of whom had four of their grandparents living close by in a rural area.
This allowed the researchers, led from Oxford University, to filter out 20th century migration and examine migration patterns dating back more than 1,000 years.
Co-author Dr Garrett Helenthal of University College London told the Belfast Telegraph that the study contradicts the notion of a Celtic relationship between people in Cornwall, Wales and Scotland. In fact, there are big genetic differences between these areas.
However, it found two distinct genetic groupings in Northern Ireland. One of these included people living across the Irish Sea in western Scotland and the Highlands, while the other shared genetic links between people in southern Scotland and southern England.
It's thought the former tribe reflects the kingdom of Dalriada 1,500 years ago; while the latter descends from the settlers of the Ulster Plantation.
But Dr Helenthal added: "It's extremely unlikely that any of these genetic differences encode for cultural differences. Individuals in different geographical regions may be somewhat isolated. And if that happens, you may start to look a bit genetically distinct from the people that you are not meeting with. If these groups are isolated they might develop their own differences in culture, but there is no reason to think that is encoded genetically."
The two tribes in Northern Ireland also show genetic similarities to modern-day populations in Belgium, north west France and parts of Germany, suggesting they share common ancestors. The study has also found that people in south Wales are quite distinct from people in north Wales; while the culturally Celtic people of Cornwall are much more similar to people in England than those in Scotland.
It's the first genetic evidence to confirm the archaeological theory that Celts represent a tradition rather than a genetic or racial grouping.