For years Irish people, along with the Scots, have been associated with red hair, fair skin and freckles.
Celtic people have carried the ginger gene for centuries but it has always been unclear as to where it actually originated.
A study carried out in Spain on the gene evolution of 1,000 people offers a new theory.
V60L allele, the ginger gene, first arrived 50,000 years ago when people left the hot climate of Africa to move north into Europe.
The shorter days and lower temperatures meant they spent less time in the sun and so absorbed less vitamin D.
To counter this lack of nutrition the human body developed. People with paler skin and red hair evolved as they are capable of soaking up vitamin D at a faster rate than those with darker tones.
There was a downside to the paler complexion though, with a higher risk of melanoma, a deadly form of cancer.
Doctor Saioa Lopez, who carried out the study told the Daily Mail: “As a consequence of depigmentation there has been a collateral damage consequence to health.”
One in ten people in Ireland have red hair and this study revealed that the gene remains dominant throughout southern Europe.
The fact that the study took place in Spain raises another interesting point.
Many believe the first people to settle in Ireland came from Galicia in northern Spain, which is possibly where the world Gaelic came from.