those mysterious green eyes!
By zteve t evans
Green eyes in humans and are considered by many people to be very beautiful, very mysterious and very alluring. But why do people have different eye coloring and what is that puts the ‘green’ into green eyes?
Melanin
A large part of the answer is the quantity of melanin found in the human iris that is decided by genetics. Eye color is determined by the DNA inherited from parents and
ancestors. It is this that will decide the levels and types of melanin which are present in the eyes. Melanin is a pigment that also found in the skin as well as the eyes. It comes in two different types which are yellow melanin and dark, black melanin. An iris with out
either yellow or black melanin appears blue.
Rayleigh scattering
Green eyes result when the upper layer of the iris, called the stroma is yellowish in color. They then appear green due to a principle that affects how humans perceive color and light called Rayleigh scattering, or selective scattering. This is a natural phenomenon which is also the reason why the sky appears blue when we look up at it and why the sun looks yellowish. Blue or green pigments are not present in the human iris so it is the Rayleigh scattering of light which causes the coloration of green eyes and also that of blue and hazel eyes.
A large part of the answer is the quantity of melanin found in the human iris that is decided by genetics. Eye color is determined by the DNA inherited from parents and
ancestors. It is this that will decide the levels and types of melanin which are present in the eyes. Melanin is a pigment that also found in the skin as well as the eyes. It comes in two different types which are yellow melanin and dark, black melanin. An iris with out
either yellow or black melanin appears blue.
Rayleigh scattering
Green eyes result when the upper layer of the iris, called the stroma is yellowish in color. They then appear green due to a principle that affects how humans perceive color and light called Rayleigh scattering, or selective scattering. This is a natural phenomenon which is also the reason why the sky appears blue when we look up at it and why the sun looks yellowish. Blue or green pigments are not present in the human iris so it is the Rayleigh scattering of light which causes the coloration of green eyes and also that of blue and hazel eyes.
Babies
Green eyes are not usually present when a baby is born. The infant’s eyes change from grey or blue, gradually to green, sometimes over several months and in some cases over several years.
Around the world
It is known that there were humans with green eyes thousands of years ago in Siberia during the Bronze Age. Green eyes are more common in Europe and with people of European ancestry. In some European countries people with green eyes out number those with brown. Around 80% of people in Iceland have green or blue eyes. Green eyes are more often found in females than males in Iceland and this is also a worldwide trait. Green-eyed people can be found all around the world though they are generally of Germanic or Celtic descent.
In Asia and Africa green eyes are very rare for the most part but do occur. One exception is Liqian, a village in Western China, where many of the villagers have blond hair along with green eyes. DNA testing revealed that around two thirds of the people who lived there were of Caucasian origin. Generally Asians or Africans with green or blue eyes have Caucasian ancestry which may be distant on both sides of their family.
It is the person that matters!
Green eyes can appear mysterious and beautiful and of course so can brown, blue, hazel and all the other tints and hues that eyes take on, but it is not the color that is important, but the person who is wearing it.
© 12/07/2013 zteve t evans
Green eyes are not usually present when a baby is born. The infant’s eyes change from grey or blue, gradually to green, sometimes over several months and in some cases over several years.
Around the world
It is known that there were humans with green eyes thousands of years ago in Siberia during the Bronze Age. Green eyes are more common in Europe and with people of European ancestry. In some European countries people with green eyes out number those with brown. Around 80% of people in Iceland have green or blue eyes. Green eyes are more often found in females than males in Iceland and this is also a worldwide trait. Green-eyed people can be found all around the world though they are generally of Germanic or Celtic descent.
In Asia and Africa green eyes are very rare for the most part but do occur. One exception is Liqian, a village in Western China, where many of the villagers have blond hair along with green eyes. DNA testing revealed that around two thirds of the people who lived there were of Caucasian origin. Generally Asians or Africans with green or blue eyes have Caucasian ancestry which may be distant on both sides of their family.
It is the person that matters!
Green eyes can appear mysterious and beautiful and of course so can brown, blue, hazel and all the other tints and hues that eyes take on, but it is not the color that is important, but the person who is wearing it.
© 12/07/2013 zteve t evans
References and Attributions
Copyright ztevetevans on July 12th, 2013
Copyright ztevetevans on July 12th, 2013