Why do some people have,one blue eye and one brown eye.?

Answer 1

Genes and alleles


Each of these pairs of chromosomes contains genes inherited from the father and genes inherited from the mother, and these genes are in pairs, both coding for the same characteristic - so you have two genes controlling eye colour, for example. These different forms of the same gene are called alleles (pronounced al-eel). The gene for eye colour has an allele for blue eye colour and an allele for brown eye colour.

If both the alleles inherited by the zygote for a particular characteristic are the same they are called homozygous). If they are different from each other they are called heterozygous. An individual who has homozygous alleles for a particular characteristic is described as purebred. In addition, alleles may be either dominant or recessive. A dominant allele always shows. A recessive allele only shows when it is on its own (because it's on a sex chromosome) or when both the alleles are the same (homozygous).



Many human characteristics are controlled by just one pair of genes, for example eyelash length, colour of the iris of the eye, shape of the upper eyelid, shape of the earlobe and the ability to taste phenylthiocarbamide (PTC). Other characteristics, such as hair colour and type, may be controlled by more than one set of genes.

A set of alleles inherited by an individual is called a genotype. The way the genes express themselves in the individual's appearance is their phenotype

Answer 2

It could be due to genetic chances, or it could also be due to prenatal development.

It has been discovered (due to repeated testing of prisoners' DNA in jails) that some people have two kinds of DNA in their bodies. The theory is that they begin in the womb as fraternal (non-identical) twins, but something goes wrong and one embryo begins to absorb the other.

This is not necessarily the same as conjoined twins, because one is so completely absorbed that the person born has all the usual arms and legs and looks like a single person.

But the person who is born can wind up having some tissues that are of one DNA and some that are of the other. They are closely related, of course-- they came from the same parents-- but you can see how this can influence a person later on in life, especially if some tissues were from a male and some from a female.

If the exterior sexual organs of the body were completely absorbed and do not remain, there may not be anything to indicate that it happened, except the subtle (hormonal?) influence of the other remaining tissues on the person's behavior, later on in life.

Eye color is probably one of the very few ways in which this could be obvious at a glance. But since there are other possible explanations for it, DNA testing can clarify the matter, to set your mind at ease.

Answer 3

for me it depends on the girl. Like I might observe a girl with black hair and also think she is totally hot yet see a girl with blond hair that is meh and vice versa.

Answer 4

According to the experts at Scientific American.com, it was once believed that eye color was controlled by a single gene and inherited in a straightforward fashion (remember Mendel from high-school biology?). These days it's not quite that simple. We now believe that eye color is a polygenic trait.

Eye color is determined by the amount of melanin, a dark brown pigment, present in your irises. Blue eyes are due to a lack of melanin, while brown eyes indicate melanin-rich irises. Thus, people with darker hair and skin have higher levels of melanin and tend to have brown eyes, while people with lighter hair and skin have lower levels of melanin and usually have lighter colored eyes. This is also why many babies are born with blue eyes. Their eyes change color later as they begin to produce more melanin.

When an individual has different amounts of melanin in each of their irises, their eyes are different colors. Heterochromia iridium (the scientific name for two different color eyes in the same individual) is relatively rare in humans but common in some animals, such as horses, cats, and certain species of dogs. A variation on the condition is heterochromia iridis, in which an individual has a variety of colors within one iris.

Heterochromia iridium is thought to result from an alteration to one of the genes that controls eye color. This can be an inherited trait, although trauma and certain medications may result in increased or decreased pigmentation in one of the irises. Certain medical syndromes, such as Waardenburg syndrome, may also cause someone to have two different colored eyes.

Some people with this condition wear colored contact lenses so their irises match, while others take pride in their striking appearance.

Answer 5

My uncle has one blue eye and one brown eye. When he and my dad were 4 (they are twins), they were playing with a toy bow & arrow set. The arrows had suction cups on the end, but the suction cup had fallen off. My dad shot that arrow at his brother (my uncle) and it hit him in the eye. Now that eye is brown and he is legally blind in it.

Answer 6

i actualy have 1.5 blue eyes and 1/2 a brown eye, kinda wierd.

Answer 7

from what i recently heard on the Discovery Channel its now believed to caused from a polygenetic trait or multiple genes rather than a single gene

Answer 8

did you know that people with colored eyes are geneticly defective??

It really is a genetic defect look it up its true 100%

Answer 9

I have 2 green eyes and one brown eye.... wink wink

Answer 10

its all genetics. the gene for eye color can differ from one eye to the next, affecting the color of the eye.

but who knows, maybe that person is wearing coloured contact lenses! :)