I know that eye colour is all about genetics, but why were early humans' eyes different colours in the first place?
2006-12-02 01:31:21 · 5 answers · asked by Rachel F 1 in Science & Mathematics ➔ Biology
Well, it has to do with proteins being produced to create pigment, and how they've changed through the process of evolution. As humans moved out of Africa, into Europe and Asia, they also began to evolve differently. In European humans, mutations occured that lightened skin and eye color. This was okay for them- in Africa, dark skin and eyes helped protect against UV damage from the sun. In Europe, where there was less direct sunlight, it wasn't as necessary to be protected. Therefore, the mutated genes were not selected out, and actually became quite common in Europe.
2006-12-02 01:44:11 · answer #1 · answered by bflute13 4 · 1⤊ 0⤋
Early humans' eyes were probably all brown. Early Caucasians appear to have acquired a mutant gene for non-brown eye color.
Caucasians also have a mutant gene for hair color - most of the world has black hair - although hair color and eye color are from different genes and there are at least two, probably three, genes involved in eye color.
Mutations happen randomly. Blue eyes (Swedes) and green eyes (Irish) have less pigmentation than brown eyes and are better adapted to the northern climates where those populations live.
That brown eyes are "normal" for humans can be seen from the northern societies (Eskimo, Aleut) who are at those same northern latitudes, but do not typically have non-brown eyes.
People with no eye pigmentation at all have red eyes (albinism) as you see the blood vessels in the back of their eye.
2006-12-02 01:53:13 · answer #2 · answered by Steve A 7 · 0⤊ 0⤋
In easy words (I took that in a physiology class):
Now, in the iris of the eye there's a special pigment, on which the eye's color is determined. People having low or no pigment will have blue eyes, since this is the original color of the iris, but the higher the pigment, the closer the eye will get to black (Light green, green, hazelnut, brown, black). It's this simple.
2006-12-02 01:41:02 · answer #3 · answered by Anonymous · 0⤊ 0⤋
The segment of DNA is gene, is acts as genetic information for expression of specific traits, since the different form of gene is allele, it very among people it determines the colour of eye..
2006-12-02 01:47:35 · answer #4 · answered by imthiyaz 1 · 0⤊ 0⤋
cos they are
2006-12-02 01:40:52 · answer #5 · answered by bigpenso 2 · 0⤊ 0⤋