DNA may hold clues to an ancient movement from Ireland to Scotland
Scientific evidence of an ancient invasion of Scotland from Ireland may have been uncovered by DNA techniques.
Researchers from Edinburgh University said studies of Scots living on Islay, Lewis, Harris and Skye found strong links with Irish people.
Early historical sources recount how the Gaels came from Ireland about 500 AD and conquered the Picts in Argyll.
Scientists said the study was the first demonstration of a significant Irish genetics component in Scots' ancestry.
The research, which features work by geneticist Dr Jim Wilson, a specialist in population genetics, is being featured in programmes on Gaelic television channel BBC Alba.
The study also suggests intriguing ancestry of Scots living on the Western Isles and in the north and north east of Scotland.
Dr Wilson said: "It was extremely exciting to see for the first time the ancient genetic connection between Scotland and Ireland - the signature of a movement of people from Ireland to Scotland, perhaps of the Scots or Gaels themselves."
The origin of the Gaels - who by conquering and integrating with Pictish northern tribes created the Kingdom of Alba - has been debated by historians for centuries.
The earliest historical source comes from around the 10th Century and relates that the Gaels came from Ireland in about 500 AD, under King Fergus Mor.
However, more recently archaeologists have suggested the Gaels had lived in Argyll for centuries before Fergus Mor's invasion.
The study also suggested an east-west genetic divide seen in England and attributed to Anglo-Saxons and Danes was evident in the north of Scotland.
This was noted in places far from Anglo-Saxon and Danish settlements, indicating that this division was older and may have arisen in the Bronze Age through trading networks across the North Sea.
Geneticists also said as many as 40% of the population on the Western Isles could have Viking ancestry, while no Viking ancestry was found in north east Scotland.