Genetics Determine our Eye Color

The eye color of a person results from pigmentation of the iris, which surrounds the pupil and helps to control the amount of light that can enter the eye. The color of the eye is mostly categorized as brown, green/hazel, or blue. Globally, brown is the most frequent color of the eye. Lighter eye colors, such as green and blue, are found mainly among people of European ancestry.
Colour of the eye is determined by variations in genes. Most genes that are associated with eye color play a vital role in the production, transport, and storage of a pigment known as melanin. Eye color is directly related to the quality and amount of melanin in the iris. Blue-eyed people have a small amount of melanin in the iris while brown-eyed people have a large amount of this pigment.
A specific area on chromosome 15 plays a key role in eye color. In this area, there are two genes that are located close together: HERC2 and OCA2. HERC2 gene contains a DNA segment that controls the activity of the OCA2 gene. OCA2 gene produces P protein that is involved in melanosomes maturation. Melanosomes are cellular structures that make and store melanin. Therefore, P protein plays an important role in the quality and amount of melanin available in the melanin. Less P protein produces less melanin in the iris, resulting in blue eyes. People with a large amount of melanin in their iris have brown eyes.
References
https://ghr.nlm.nih.gov/primer/traits/eyecolor
http://www.gbhealthwatch.com/Trait-Eye-Color.php

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