Your eyes can be a window into his soul, and some say they have their eyes – blue, attractive or deep green, baby mysterious Brown -. may reveal even more
like how well you tolerate pain. Or your tendency to alcohol dependence . Or generally enjoyable it can be.
eye color and eye color which means really are a constant source of fascination among scientists, academics and that boy or girl across the bar. As often it happens with these things, however, is not so simple. In fact, it becomes quite complicated
What you see is what you get
“This general question of the relationship between, for example, a visible feature. – Height or body size, or color of skin or eye color or hair color – and everything else, whether it is a feature of disease or whether it is a visible feature is something the geneticists think and talk all the time. and is a subject of popular interest understandable, “says Greg Barsh, a researcher at the faculty in the HudsonAlpha Biotechnology Institute, a nonprofit organization based in Huntsville, Alabama, and professor emeritus of genetics at Stanford University.
“we do not believe, do not believe that there is a direct connection eye color with specific diseases. we do not believe that there is a relationship, for example, between the color of the eyes and diabetes, or eye color and cancer, or color and eye behavior. “
However, many people are too willing to make that link between the color of someone’s eyes and for example, react how well test motor skills . (Men with dark eyes reportedly performed better than those with eyes lighter in color – but only when blue racquetballs, rather than green or yellow)
People eye. clear from a particular region, for example, actually less pleasant than the population of dark eyes in the same region as a study suggests
it’s easy accept hypothesis of this study , which concludes that “clear-eyed people have a higher prevalence of [alcohol dependence] that individuals with dark eyes.” O this piece in the capital , based on several popular items, which concludes:
- brown-eyed people are prone to anxiety.
- green-eyed people have a higher tolerance for pain.
- People with blue eyes have a lower risk of anxiety and depression, however, they are more likely to become alcohol dependent.
Easy, safe. But credible? Can you really make that leap, that generalization, based solely on the color of someone’s eyes? Or is it, as Barsh, more complicated suggest?
lineage, cause and correlation
“Most individuals with color blue eyes are of northern European descent. But there are many other features that are also correlated with ancestry from northern Europe, “says Barsh. “So when someone says, ‘Well, I looked at a group of people with blue eyes and discovered that lead faster, or who die before, or have a difference of pain tolerance ‘. .. the question always default to be asked is: “How do you know that is not a difference that is genetic and happens to be related to their ancestry from northern Europe? ”
Barsh cites an old popular example among geneticists: A discovery makes people in the San Francisco Bay Area are more skilled, as a whole, using sticks that people in many other parts of the country. is that because, simply, that the [redesdeeláreadelabahía?
or is because many people of Asia, and many people with ancestors from Asia, have settled in the area of San Francisco, and ancestors were adept to eat with chopsticks?
“the situation with visible features is actually quite similar, because the visible features are very highly correlated with ancestry, “he says Barsh. in other words, blue eyes are often passed down from ancestors in northern Europe. people with ancestors from Asia and Africa are usually dark eyes.
However, that does not mean you can draw conclusions about diseases or behaviors simply based on descent, either.
“One of the main challenges that I think we all face biologists distinguish correlation from causation “adds Barsh. “If you have two traits found in a group but not another, it can be very difficult to distinguish whether the relationship between the traits that one causes the other, or just happened to be present in the same population.”
so to do this right, you have to dive deep into the genetics of a population. And genetics are a complicated thing. There is a major gene – called the OCA2 – responsible for eye color, for example. However, several other genes contribute. Therefore the allocation of a behavior, or the possibility of getting a disease, for example, OCA2 and four or five genes (including about 20,000 in humans) remains a bit on the simplistic side.
“we know enough about the genes that control skin and eye color [know] that is, in fact, all they do. they do not do other things,” says Barsh. “No matter how much we learn, we’ll never learn who has the eye color nothing to do with intelligence . We know it’s not. It has nothing to do with behavior. It has nothing to see with susceptibility to disease. “
the only exception, it seems, is that people with lighter skin and lighter eyes are more susceptible to the harmful effects of the sun’s ultraviolet rays, which could lead to eye diseases and skin
Apart from that, however, the color of the baby blues is that and only that. a color (or lack of, or a combination of colors) based on the genes inherited from their ancestors.
Everything else may be just your eyes playing tricks.