Raquel Sauer
Anthropology 1020-101
1. Introduction
Heredity and Blue Eyes 04 August 2014
Final Paper
Heredity, our heredity, and just exactly how did we get here? This paper lightly touches on heredity as it relates to chromosomes, genes, mutations and medical implications, and our eyes. In biology and health classes instructed over the years, we were all taught that there were 23 chromosome pairs
– pairs 1-22 developed the body – and pair 23, the sex chromosomes. Chromosome 15 is the one we are most interested in because it and specifically gene OCA2 is what gives us skin, hair, and eye color
According to a University of Copenhagen research team, blue eyes come from brown eyes. They tracked down a genetic mutation they say occurred 6,000 – 10,000 years ago and they say all blue eyed humans have the same ancestor. Professor
Eiberg from the research team says the affected gene acts as a gene switch and
“turned off” the ability to have brown eyes; and at one point all humans on the planet had brown eyes. We need to consider brown eyes as the “default” color of all human eyes.
2. Theory
Chromosome 15 and the OCA2 gene provide genetic plans for making a protein called the P protein. This protein is located in melanocytes, which are specialized cells that produce melanin and that gives us our skin, hair, and eye color.
Although the exact function of the P protein is unknown, it is essential for normal pigmentation and is likely involved in the production of melanin. Within melanocytes, the

Raquel Sauer
Anthropology 1020-101
Heredity and Blue Eyes 04 August 2014
Final Paper
P protein may transport molecules into and out of structures called melanosomes
(Genetics Home Reference, National Institute of Health, US Gov.).
Professor Eiberg, Depart of Cellular and Molecular Medicine, and his researchers first identified the OCA2 gene as the responsible source of eye color in 1996 His team examined mitochondrial DNA and compared people with blue eyes in diverse countries such as Jordan, Turkey, and Denmark. They have spent over a decade conducting this ground-breaking research (Copenhagen).
Here is something else to consider. We have been taught over and over in classes that both blue-eyed parents cannot produce children with brown eyes. That is actually a myth. According to McDonald, medical studies conducted as early as 1909 revealed that the notion of blue eyed parents capable of only having blue-eyed children was false. It’s not a mathematical equation that blue +blue= blue. The ability of genes to cause mutations, even very slight ones, can occur unexpectedly and more often than we think.
3. Animal and Human Eyes
Blue eyes can be found in both animals and of course, humans. Blue eyes can be found in cats, dogs, cattle, reptiles and snakes, birds, and yes, even koala bears!
Think about it though, there is no reason why animals, birds, reptiles and amphibians can’t have blue eyes. Even though their chromosomes are different, they can have the same kind of mutations that humans have. Melanin is the source of their colors too, and less of it means different eye colors instead of brown.

Raquel Sauer
Anthropology 1020-101
Heredity and Blue Eyes
Here are some examples of different creatures with blue eyes.
Cats
04 August 2014
Final Paper
Birds
Koala Bears

Raquel Sauer
Anthropology 1020-101
Humans
Heredity and Blue Eyes 04 August 2014
Final Paper
Are there any mutation issues if the OCA2 gene does not copy correctly? Yes there is and mutations in the OCA2 gene disrupt the normal production of melanin, which reduces coloring of the hair, skin, and eyes and affects vision (melanin is also in the back of the eye). The lack of OCA2 can directly or indirectly lead to lack of eye color, but not having it can lead to mental and physical disabilities. Here are three examples of OCA2 mutations and what they do:
Oculocutaneous Albinism - caused by mutations in the OCA2 gene and there are over 80 mutations in the OCA2 gene have been identified in people with oculocutaneous albinism type 2. People with this form of albinism often have light yellow, blond, or light brown hair; creamy white skin; light-colored eyes; and problems with vision.
Angelman syndrome – is caused by the OCA2 gene that is located in a region of chromosome 15 that is often deleted in individuals with Angelman syndrome. People with this condition who are missing one copy of the OCA2 gene tend to have unusually

Raquel Sauer
Anthropology 1020-101
Heredity and Blue Eyes 04 August 2014
Final Paper light-colored hair and fair skin. Cells with only one copy of the OCA2 gene make a reduced amount of P protein, which affects the coloring of the hair and skin.
Prader-Willi syndrome – linked to the OCA2 gene which is missing in individuals with this syndrome. A loss of this gene does not cause intellectual disability and the other characteristic features of Prader-Willi syndrome (PWS); however, people with this condition who only have one set of the OCA2 gene tend to have unusually light-colored hair and fair skin. Characteristics of PWS is low muscle tone, short stature, incomplete sexual development, cognitive disabilities, problem behaviors, and a chronic feeling of hunger that can lead to excessive eating and life-threatening obesity (Prader-Willi
Syndrome Association, 2014).
4. Conclusion
As we have all been taught over the years, chromosomes are the building blocks of our lives. Each of the 23 chromosome pairs are critical to our functioning as humans physically, sexually, psychologically, our traits and characteristics; to name just a few of the essential work of the chromosomes.
The OCA2 gene is what helps give us our skin, hair, and eye color. The amount of melanin or lack of it, can determine whether we have brown eyes (the human default eye color), or some variation of green, amber, blue, golden, or other combinations.
Also, the lack of it or the over different kinds of known mutations can cause a variety of skin, hair, and eye issues. One of the rarest yet very unique is the impact that the
Prader-Willi syndrome can have on a human and the quality of life issues it poses.

Raquel Sauer
Anthropology 1020-101
Heredity and Blue Eyes 04 August 2014
Final Paper
Blue eyes are not a uniquely human trait and characteristic. It can be seen throughout the animal, bird, reptile and amphibian world. In my own family, my husband, 3 children, and myself, all have some variation of blue eyes. My father has brown eyes and my mother blue eyes. All four of us off-spring have blue eyes and no hint of brown at all!!
http://ghr.nlm.nih.gov/. Genetics Home Reference. 03 August 2014. On-line. 03 August 2014.
McDonald, John H. Myths of Human Genetics. Baltimore: Sparky House Publishing, 2011. On-line.
University of Copenhagen. "Blue-eyed Humans Have A Single, Common Ancestor." Science Daily 31
January 2008: 2. Print.