Admin Admin
Posts : 638 Points : 2155 Reputation : 19 Join date : 2010-05-15 Age : 37 Location : islamabad
| Subject: EYE COLOURS AND THIER CHARACTERISTICS Fri Jun 11, 2010 9:03 pm | |
| Eye color is a polygenic phenotype character and is determined by the amount and type of pigments in the eye's iris.[You must be registered and logged in to see this link.] Humans and animals have many phenotypic variations in eye color, as blue, brown, green and others. These variations constitute phenotype traits.Genetic determination of eye colorEye colors can range from the most common color, brown, to the least common, green. Eye color is an inherited trait influenced by more than one gene. These genes are being sought using associations to small changes in the genes themselves and in neighboring genes. These changes are known as single nucleotide polymorphisms or SNPs. The actual number of genes that contribute to eye color is currently unknown, but there are a few likely candidates. Blue eyes with a brown spot, green eyes and gray eyes are caused by an entirely different part of the genome. Classification of colorsIris color can provide a large amount of information about an individual, and a classification of various colors may be useful in documenting pathological changes or determining how a person may respond to various ocular pharmaceuticals. Various classification systems have ranged from a basic light or dark description to detailed gradings employing photographic standards for comparison. Others have attempted to set objective standards of color comparison.Eye color chart (Martin-Schultz scale)Carleton Coon created this chart by the Martin-Schultz scale often used in physical anthropology.
- Light eyes
Eyes light and light mixed are 16-12 in Martin scale.LightGray, blue, green.Light-mixed
- Very
light-mixed (blue with gray or green or green with gray)
- Light-mixed
(light or very light-mixed with small admixture of brown pigment)
- Mixed eyes
Mixed12-6 in Martin scale. Mixture of light eyes (blue, gray or green) with brown pigment when light and brown pigment are the same level.
- Dark eyes
Dark-mixed6-4 in Martin scale. Brown with small admixture of light pigment.Dark4-1 in Martin scale. Brown (light brown and dark brown) and very dark brown (almost black).Amber (Untruthful , selfish type)[You must be registered and logged in to see this image.]
[You must be registered and logged in to see this link.]Amber iris[You must be registered and logged in to see this image.] [You must be registered and logged in to see this link.]Human female with an amber iris[You must be registered and logged in to see this image.] [You must be registered and logged in to see this link.]Human amber eyes displaying the yellow pigments.Amber eyes are of a solid color and have a strong yellowish/golden and russet/coppery tint. This might be due to the deposition of the yellow pigment called lipochrome in the iris (which is also found in green eyes). Amber eyes should not be confused with hazel eyes; although hazel eyes may contain specks of amber or gold, they usually tend to comprise many other colors, including green, brown and orange. Also, hazel eyes may appear to shift in color and consist of flecks and ripples, while amber eyes are of a solid gold hue.Blue ( Extremely Passionate people)[You must be registered and logged in to see this link.] [You must be registered and logged in to see this image.]
A blue irisBlue eyes contain low amounts of melanin within the iris stroma; longer wavelengths of light tend to be absorbed by the underlying iris pigment epithelium, and shorter wavelengths are reflected and undergo Rayleigh scattering. Distribution of light-eyed (blue, green, gray) persons in EuropeBlue eyes are most common in Northern Europe and Central Europe and to a lesser degree in Southern Europe (through migration of Northen European and Central European settlers) and southern Central Asia; Afghanistan is a notable example. They are also found in parts of North Africa, West Asia, and South Asia in particular the northern areas of India and Pakistan.Brown (Move around themselves)"Brown eyes" redirects here. For other uses, see. [You must be registered and logged in to see this link.][You must be registered and logged in to see this link.][You must be registered and logged in to see this image.]
Brown iris [You must be registered and logged in to see this link.][You must be registered and logged in to see this link.][You must be registered and logged in to see this image.]
Light brown irisBrown eyes are dominant in humans and in many parts of the world; it is nearly the only iris color present. It is less common in countries around the Baltic Sea and in Scandinavia. Dark pigment of brown eyes are most common in East Asia, Southeast Asia, Oceania, Africa, South America and the Middle East.Gray (Optimistic People) [You must be registered and logged in to see this link.][You must be registered and logged in to see this link.][You must be registered and logged in to see this image.]
A steel blue-gray iris [You must be registered and logged in to see this image.] Gray iris under magnification, exhibiting small amounts of yellowGray eyes are most common in European Russia, Sweden, Finland and the Baltic States. It can also be found to a lesser extent in parts of India. Under magnification, gray eyes exhibit small amounts of yellow and brown color in the iris. Visually, gray eyes often tend to appear to change between the shades of blue, green and gray; this is because gray eyes are, as already mentioned, extremely light.Green ( Bewafa log hoty hain, not sincere)[You must be registered and logged in to see this link.] [You must be registered and logged in to see this image.]A light green iris with small amounts of brown [You must be registered and logged in to see this image.] [You must be registered and logged in to see this link.] Olive green eyes Green eyes are the product of low to moderate amounts of melanin and probably represent the interaction of multiple variants within the OCA2 and other genes. Green eyes are most common in Northern and Central Europe. They can also be found in parts of Southern Europe (through migration of Northen European and Central European settlers), South Asia[You must be registered and logged in to see this link.], West Asia, and North Africa. In Iceland, 89% of women and 87% of men have either blue or green eye color.Hazel (With Lot of Attitude) [You must be registered and logged in to see this link.][You must be registered and logged in to see this link.][You must be registered and logged in to see this image.]
Hazel eyes are due to a combination of Rayleigh scattering and a moderate amount of melanin in the iris's anterior border layer. Hazel eyes often appear to shift in color from a light brown to a dark golden-green. Red ( Anger, and Aggressions)[You must be registered and logged in to see this link.] [You must be registered and logged in to see this image.]
"Red" albino eyesThe eyes of people with severe forms of albinism may appear red under certain lighting conditions owing to the extremely low quantities of melanin, allowing the blood vessels to show through. In addition, flash photography can sometimes cause a "red-eye effect", in which the very bright light from the flash reflects off the back of the eyeball, which is abundantly vascular, causing the iris to appear red in the photograph | |
|