Study Links Blue Eyes to a Common Ancestor Dating Back Thousands of Years Ago

A study conducted by a team at the University of Copenhagen has shed light on the origins of blue eyes. 

The research, led by Professor Hans Eiberg from the Department of Cellular and Molecular Medicine, has found that all blue-eyed individuals may share a single and common ancestor who lived between 6,000 and 10,000 years ago.¹

The Genetic Mutation

The study focused on a genetic mutation that occurred in the OCA2 gene, which is responsible for the production of melanin in the eyes. 

This mutation resulted in the creation of a “switch” that literally “turned off” the ability to produce brown eyes, leading to the emergence of blue eyes among humans.

Limited Genetic Variation

The researchers found that blue-eyed individuals have a limited degree of variation in the amount of melanin in their eyes, indicating that they all inherited the same genetic mutation at the same spot in their DNA. 

In contrast, brown-eyed individuals have considerable individual variation in the area of their DNA that controls melanin production.

Common Ancestor

The study suggests that this genetic mutation occurred only once, and all blue-eyed individuals today are linked to this single ancestor. 

The surrounding DNA regions, known as haplotypes, were found to be identical for almost every single individual tested, further supporting the theory that the mutation arose from a common ancestor.

Origins of Blue Eyes

The genetic mutation is believed to have originated in the Black Sea region of Europe around 6,000 to 10,000 years ago. 

This region was characterized by low sunlight, making lighter skin and fairer hair beneficial for Vitamin D production. The blue-eyed trait spread as populations dispersed, becoming prominent in Northern Europe.

The study provides strong evidence that all blue-eyed individuals share a common ancestor who lived thousands of years ago. The genetic mutation responsible for blue eyes is a neutral mutation, neither increasing nor decreasing the chances of survival, but rather a natural variation that has been shaped by the environment and natural selection.

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Source:

1. https://www.sciencedaily.com/releases/2008/01/080130170343.htm