Green eyes possess low to moderate amounts of melanin(which is what makes brown eyes brown) and probably represent the interaction of multiple mutations in the OCA2 gene and others. Recently the Mendelian recessive trait theory has been disproven. What we were taught in school about eye color before 2007 was not correct. The Mendelian theory stated brown eye color was dominant over blue, so a person with two brown genes or a brown and a blue gene would have brown eyes, and only two blue genes with no brown gene could make blue eyes. The study disproving the Mendelian theory was published in the American Journal of Human Genetics, and was supported with grants from Australia’s National Health and Medical Research Council and the United States of America’s National Cancer Institute.
To understand green eyes, first we have to look at blue and brown eyes. Researchers do not know if people with blue eyes shared one common ancestor, this is an ongoing argument that scientists are trying to learn. There is significant evidence that the first people had only brown eyes. A mutation most likely occurred only 6-10,000 years ago to spur human reproduction during a time of sparse food, epidemic, or something that was killing off massive amounts of people. Blue eyes first were seen in areas of northern latitudes where there are shorter hours of daylight, this could POSSIBLY play a big role, because blue eyes allow more vitamin d to be let in, thus preventing people with the traits of light skin and blue eyes to develop diseases such as rickets. Being such a rare color and representing health in these areas, brown eyed people instinctively wanted to have children with the blue eyed/light skinned people. Brown eyed people with darker skin are better equipped to handle sunny areas where there are longer daylight hours. Blue eyes carry a low amount of melanin compared to brown eyes. When you mix blue and brown eyes you might get green eyes. Only rarer are violet, which are exclusively found in the Kashmir Mountain Region, an area that is currently disputed between Pakistan and India, these are borderline albino eyes. And then finally red eyes, which is a product of the genetic condition albinism.
So that brings me to green eyes finally.
We do know for a fact that green eyes tend to appear in places where blue eyed people came into contact with brown eyed people probably a direct effect of evolution. Countries such as Iran, Pakistan, Afghanistan, Central Asia, Spain, northern Africa and Brazil all have had people with green eyes for a long time. When the moors invaded Spain, green eyes appeared. All races, white, black, asian, hispanic, native american’s all can have green eyes, this is perhaps what makes them so odd. While brown eyes are seen in every race, so are green eyes, which are extremely rare. This helps to prove that green eyed people could all be related. Warriors in Northern Europe, including Russia invaded countries to the south and found the darker women exotic and different. They had children with them, left some women/their offspring behind and brought others back, thus producing green eyed children around the world.
Only about 2% of the world’s population have green or hazel eyes, most of them being female.
Here are some interesting unproven traits that green eyed people are said to posses:
Green eyes are said to be magical. People with green eyes tend to have long lasting relationships. They are the most passionate. People with green eyes are said to be handsome. It also has been said green eyed people are jealous, such as the saying “green with envy”. Green eyed people may have liver or other digestive problems. In a non scientific survey, green eyes are said to be a powerful aphrodisiac.