Actually teach was probably the closest to being right in here, I had a friend who wrote a paper in college on this topic and it became a very big discussion in class.
Second off I want to say that genetree.Com sight chart about eye color says it originates from the 1800s. And though its slightly accurate on alleles the table it represents could never be used and any accuracy that came out of it would be chance.
If you would like to know the scientifics on what actually decides the eye color I will explain it as simple as I can without losing anyone...
The eye color is decided by the amount of pigment (called melanin) in the iris of the eye. For example: blue eyes have little pigment in them while brown eyes have alot. Melanin is a dark brown pigment that is deposited on the front surface of the iris. If a lot of melanin is present, the eye will appear brown or even black. If very little melanin is present the iris appears blue. Intermediate amounts of melanin produces gray, green, hazel or varying shades of brown. And what decides the amount of pigment in an iris is a number of different genes.
Like the genes when a sperm and egg cell is created they each have a haploid number of 23 chromosomes and during pregnancy, the fertilized egg undergoes a series of changes including multiple cell divisions and differentiation of cells into the different organ systems. The result is a baby whose cells each have 46 chromosomes.
one chromosome of each pair is inherited from the baby's father and the other from the mother. And we all know genes are what determine the observable characteristics (eye color) in humans.
| research paper from osu wrote: |
at the present, three gene pairs controlling human eye color are known. Two of the gene pairs occur on chromosome pair 15 and one occurs on chromosome pair 19. The bey 2 gene, on chromosome 15, has a brown and a blue allele. A second gene, located on chromosome 19 (the gey gene) has a blue and a green allele. A third gene, bey 1, located on chromosome 15, is a central brown eye color gene. |
this means that there is a dominance order among the two gene pairs. If a person has a brown allele on chromosome 15 and all other alleles are blue or green the person will have brown eyes. If there is a green allele on chromosome 19 and the rest of the alleles are blue, eye color will be green. Blue eyes will occur only if all four alleles are for blue eyes. This explains the inheritance of blue, brown and green eyes but cannot account for gray, hazel or multiple shades of brown, blue, green and gray eyes. It can't explain how two blue-eyed parents can produce a brown-eyed child(which genetree.Com says 2 blue-eyed parents can not have darker eyed children). This suggests that there are other genes, yet to be discovered, that determine eye color or that modify the expression of the known eye color genes.
So unless you know the specific order of those two pairs of genes your not going to be able to accurately make up a "table" for predicting the eye color of your baby.
Im sorry for the exhaustive post but I just like to get facts out there rather than alot of assumptions that make people go in circles.