Researchers at the University of Pittsburgh can see a link between eye color and how much people feel pain and how well they hold their alcohol, Sunday World reports.
People once thought that there was one gene for blue eyes and one gene for brown eyes, which is taught in most science classes with Punnett squares. Scientists now know that it takes many different variations in genes to create eye color, which may explain the link between eye color and so many aspects of people’s lives, according to the Daily Mail.
“What we know now is that eye color is based on 12 to 13 individual variations in people’s genes,” said Dr. Jari Louhelainen, a senior lecturer in biomolecular sciences at Liverpool John Moores University. “These genetic markers give us a good chance of telling someone’s eye color. We can predict eye colour with between 70 per cent and 90 per cent accuracy.”
“These genes do other things in the body. One of them, NCX-4, which is linked to darker eyes, controls many proteins, of which one has recently been linked to pain.”
Inna Belfer, one of the researchers, studied 58 Caucasian pregnant women and found that women with blue or green eyes experienced less pain than women with brown or hazel. The women with lighter colored eyes also had less anxiety after giving birth and lower rates of postpartum depression.
Genes linked to melanin, a pigment that makes eyes darker, are also connected to pain, which may explain why people with darker eyes experience more pain. Melanin may also make people more susceptible to alcohol.
Psychologists at Georgia State University found that people with lighter colored eyes drink more alcohol than those with dark eyes. People with darker eyes are less likely to become alcoholics because they don’t need to consume as much alcohol to be intoxicated.
Many other studies have been done that find more links between with eye color and genetics. A study done in the 1990s also showed that people with darker eyes performed better on timed intelligence tests because they tend to think faster, while people with lighter eyes have slower reactions because they tend to think more strategically.
But not everything is black and white when it comes to these studies.
“Because of the multiple genes involved, it is a very complex picture,” Dr. Louhelainen said.