How People With Blue Eyes Are Linked To A Common Ancestor
The first set of blue eyes discovered apparently belonged to a seven thousand year old skeleton found in Northern Spain. A genetic study had to be done since the eyes had obviously decayed, and it revealed that the eyes of the skeleton had been blue.
Blue-eyed people are all linked to one common ancestor- according to some recent research. More than ten thousand years ago all humans had brown eyes, but over time and with migration to different parts of the world, eye color in some people became as light as blue.
Blue eyes are a trait inherited from a single European who is thought to have existed six thousand to ten thousand years ago. These blue eyes are caused by a mutation, which affects the production of melanin- the pigment that gives our hair, eyes and skin color. According to Hans Eiberg and his team from the University of Copenhagen, this mutation occurred on the gene adjacent to the one responsible for the production of melanin. Some type of ‘switch’ was created, which in turn caused the melanin-producing gene to reduce the amount of pigment in the eye. Therefore, eye color ranges from a deep brown to green to blue, which is the color that indicates the least amount of melanin in the iris.
The study was done on blue-eyed individuals from Turkey, Denmark and Jordan. They had their DNA tested, and it was discovered that they all shared the same sequence at the same spot in their DNA. This sequence is the ‘switch’ that causes them to have blue eyes. Therefore, they’re all linked to the same ancestor.
It’s noted that most people with baby blues are of European descent, and that the mutation probably came about in the north west part of the Black Sea, around the time humans began migrating from Africa to Europe. There are a couple of theories why this mutation could have happened. Lighter eyes mostly thrive in areas where they’re not a liability, like Europe, where the exposure to UV light is lower compared to somewhere like Africa- which mostly has brown-eyed individuals. Low UV usually means that less melanin is produced, and with time this probably affected the amount of pigment that was produced in the eyes. This is what probably led people to believe that it’s a recessive trait, or a weak gene. It’s important to note however that this mutation is just one way of nature shuffling our genome and trying out different things in the process.
Other factors like a less-nutritional diet and sexual selection could have also contributed to this mutation. The gene is usually carried by females, and at one point in time it was probably thought to be attractive and the trait was then carried on.
In conclusion, all blue-eyed people are descended from the same person, although this person’s identity is still a mystery. It’s also interesting to note that this mutation is independent of race and nationality, and is simply a matter of chance and interbreeding.