2006-09-26 07:09:35 · 10 answers · asked by blackdoves_x 1 in Science & Mathematics ➔ Biology
Not like genetics, why are they coloured and why not purple or other colours
2006-09-26 09:50:34 · update #1
Eyes are coloured because the irises have pigments in them.
Genetically there are two basic eye colours brown and blue.
You have two copies of each gene, one inherited from each of your parents. If you inherit a brown gene from either parent then you will have brown eyes. In individuals which have one brown and one blue gene, the brown-eye gene is always dominant over blue as its presence ensures that the brown pigment is produced, which will 'drown out' the blue specified by the other copy of the gene. Only two copies of a blue-eye gene, one inherited from either parent will ensure a blue-eyed offspring.
There are additional complications since only one copy of each gene is expressed in each cell of the iris, so there can be a mosaic of colours at the cell level which may appear as a single colour or sometimes there is a dark ring around a paler iris. Also, there are modifier genes which restrict the levels of pigment produced which means that you can have either dark or light blue eyes and variations of green which run into blue.
You couldn't have purple eyes because there is no red pigment involved. There are some poor people and animals who have genetic variants which prevent them producing any pigment at all. They have completely white hair and skin and their eyes are pink - which is a reflection of the inside of the eye. These indviduals have no protection from ultraviolet from the sun and their eyes (and skin) are easily damaged. These are albinos.
2006-09-26 11:11:43 · answer #1 · answered by Anonymous · 0⤊ 0⤋
Genetics
2006-09-26 07:10:56 · answer #2 · answered by missymouth1 3 · 0⤊ 0⤋
it is because of geneiths. due to genetics our traits such as eye colour are herity. you are made up of DNA from your dad and mom your eye colour is probably the same as on of theirs because the dominate gene took over in eye colour blue is dominate to brown but if your parents a heterzygots with means that posit 2 traits for eye colour u may have a different colour eves than them
2006-09-26 09:05:10 · answer #3 · answered by red_star_56 4 · 0⤊ 0⤋
same reason we have different colour hair, different size feet, different body shapes... need i go on..its down to genes
2006-09-26 07:15:33 · answer #4 · answered by Anonymous · 0⤊ 0⤋
we all have recessive and dominate genes we inherited from our parents. depending on which gene you recieved will determine your eye color as dark eyes are dominate and blue green are recessive..
2006-09-26 07:18:39 · answer #5 · answered by sissybombay 1 · 0⤊ 0⤋
You may as well ask - Why do people look different?
2006-09-26 07:12:08 · answer #6 · answered by Anonymous · 0⤊ 0⤋
Same reason as for different color skin, different color hair, different shape of nose, different length of .......
Genes.
2006-09-26 07:12:25 · answer #7 · answered by Michael R 4 · 0⤊ 0⤋
because of the mix of dna from our parents
2006-09-26 07:11:33 · answer #8 · answered by ToniLianne 4 · 0⤊ 0⤋
Because you are special.
2006-09-26 07:11:19 · answer #9 · answered by Anonymous · 0⤊ 0⤋
To make girls look pretty.
2006-09-26 07:11:22 · answer #10 · answered by Anonymous · 0⤊ 0⤋