- In 1907, Charles and Gertrude Davenport outlined the basics of eye color by saying that Brown eye Color is always dominant to Blue Eye Color.
- Eye color is inherited as a polygenic not as a monogenic trait. So, to put it simply, this means that eye color is controlled by many different genes.
- Human eye color comes from melanocytes: cells which make the brown pigment melanin
- Melanocytes are cells making melanin and melanosomes are bodies in the cytoplasm storing melanin.
- In the eye, melanin is not made continuously like in skin and hair.
- Individuals with lower melanin pigments in skin, hair, and eye color who are exposed to more environmental UV light are at higher risk for developing both melanoma
- oculocutaneous albinism II (pink-eye dilution homolog, mouse)
- The OCA2 gene is located on the long (q) arm of chromosome 15 between positions 11.2 and 12
- More precisely, the OCA2 gene is located from base pair 25,673,627 to base pair 26,018,060 on chromosome 15.
- The OCA2 gene (formerly called the P gene) provides instructions for making a protein called the P protein
- This protein is located in melanocytes, which are specialized cells that produce a pigment called melanin.
- Melanin is the substance that gives skin, hair, and eyes their color (the more melanin a person has on the iris, the darker the eye color)
- Melanin is also found in the light-sensitive tissue at the back of the eye (the retina)
- The MC1R gene provides instructions for making a protein called the melanocortin 1 receptor.
- This receptor plays an important role in normal pigmentation. The receptor is primarily located on the surface of melanocytes, specialized cells that produce melanin
The Composition of the Human Eye and Information about The Eye
This is a picture of what melanin looks like. The signifcance of melanin is that it determines the color of somebody's eyes. The more the melanin found in the iris, the darker a person's eye color will be. The less amount of melanin results in a light eye color such as hazel.
Human Eye Anatomy
In this photo, all of the parts of the eye and the anatomy of an eye are displayed.
What Does Melanin Look Like?
As you see here in the diagram, this picture shows you where melanocyte and melanin are found in cells. Remember, the amount of melanin in the eye determines a person's eye color! A lack in melanin is a major cause in heterochromia, creating different pigments in the iris.