All blue-eyed people reportedly share a single common ancestor
19 Oct 2022
Research suggests that all blue-eyed people's genes for eye color originated from a single person that walked the Earth about 6000 to 10000 years ago. According to World Atlas data, around 8 to 10 percent of the human population on Earth has blue eyes, making it rarer than the most commonly found brown eye.
A team of scientists at the University of Copenhagen in Denmark took on the task of analyzing the genetic material from the Copenhagen Family Bank. This data went through three generations of genetics and found that blue eyes happen when the gene for brown eyes are "switched off".
The OCA2 gene codes for darker melanin pigment that results in brown eyes. Scientists originally believed that blue eyes meant the absence of this gene. This research however puts forward a different perspective. It is the presence of another gene, the HERC2 gene that removes the possibility of having brown eyes.
Professor Hans Eiberg from the Department of Cellular and Molecular Medicine at the University of Copenhagen explained in his 2008 research paper "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."