Origins of Blue Eyes

Today we look at the claim that people with blue eyes come from a common ancestor who lived around 10,000 years ago.

The Claim is True.

Danish geneticist Hans Eiberg pioneered studies in this area dating back to the early 1970’s. In 2008, he published a study which confirmed that blue eyes were a genetic mutation by a single person who lived 6,000 to 10,000 years ago. He stated that the genetic mutation probably originated in Europe, descended from a single ancestor, and spread throughout the world from there. Einberg also suggested that the first person who carried the blue-eyed mutation had brown eyes – not blue eyes – but passed it on to his or her offspring. This person’s child would have been the first person born with blue eyes.

“Originally, we all had brown eyes, but a genetic mutation affecting the OCA2 gene in our chromosomes resulted in the creation of a “switch”, which literally “turned off” the ability to produce brown eyes,” Eiberg wrote.

In February of 2008, USA Today published an article on Eiberg’s research.  The article quote below tells of an experiment that seemingly confirmed Eiberg’s hypothesis:

“Eventually, Eiberg was able to trace the trait for blue eyes to a specific area near the gene OCA2. Next, the Copenhagen team tested 155 people from Scandinavia, Turkey, Jordan and India, all of whom had blue eyes, to see if they had similar DNA sequences in that gene. They weren’t just similar; they were identical. That told the scientists that the mutation for blue eyes happened so recently that it hadn’t had time to change.”

Currently over 300 million people have this mutation, but it is not always apparent in certain areas of the population. Some countries have residents with prominently blue eyes while others have a far lower incidence. Estonia, for example, boasts a population of around 99% blue-eyed people. Other Scandinavian countries have a 90+% blue-eyed population.

Because of the prominence of blue eyes in certain areas of the world, it has been suggested that this trait may have played some role in reproduction.

Eiberg has also researched Batten disease, cystic fibrosis and the human genome.

Latest Research

In 2006, the skeletal remains of a Stone Age man were discovered in a cave located in Spain. A January 2014 article in the Telegraph detailed the latest findings in relation to the remains which were published in a peer-reviewed scientific journal called Nature. The skeleton was approximately 7,000 years old, and belonged to a 5ft 7in male who lived to be 30-35 years of age. DNA testing of a tooth revealed that the Mesolithic man had the dark-skinned genes of an African as well as the gene which indicated he had blue eyes. This discovery indicates the oldest known instance of blue eyes.

Dr. Carles Lalueza-Fox of the Institute of Evolutionary Biology in Barcelona made the following comments about the discovery:

“The biggest surprise was to discover that this individual possessed African versions of the genes that determine the light pigmentation of the current Europeans, which indicates that he had dark skin… Even more surprising was to find that he possessed the genetic variations that produce blue eyes in current Europeans, resulting in a unique phenotype in a genome that is otherwise clearly northern European.”

Blue Eyes and Alcohol Dependence

In June 2015, it was reported that a study found a higher chance of alcohol dependence in those with blue eyes as compared to people of other eye colors. Researchers found that the genetic components which determine eye color are aligned on the same chromosome as genes related to alcohol dependence. The authors stressed that alcohol dependence is a complex disorder and that more research is needed to better understand these findings.

Bottom Line

Blue eyes likely originated from a genetic mutation which is now widespread. Scientific research continues to show evidence that people with blue eyes have descended from a common ancestor who lived about 10,000 years ago. Hans Eiberg, a Danish geneticist, has pioneered research in this area of study. In early 2014, research was published which detailed the discovery of a 7,000 year-old skeleton in Spain that genetically confirmed the earliest known incidence of a person possessing blue eyes. In 2015, research showed a possible correlation with blue eyes and a higher incidence of alcohol dependence.

Updated July 2, 2015
Originally published August 2013