Biology 102:
I know the basic blue eyes/brown eyes deal about what is and isn't genetically possible according to the good ol' punnet squares from high school biology. My question: what are the genetics involved in green eyes, and what are the genetics involved in hazel-colored eyes?
I know it isn't as straightforward, but I think what I'm trying to figure out is what is and isn't genetically possible to have happen. (Like, two parents with blue eyes shouldn't be able to have a brown-eyed kid- is there an equivalent with green eyes and/or with hazel eyes?)
I think that blue/brown eye color is much more complicated than we learned in high school biology.
There are several genes that control eye color and it is actually possible for two blue eyed parents to make a baby with brown eyes or green eyes or hazel eyes or yellow eyes or gray eyes or violet eyes or any other color of eyes.
Eye color comes from a combination of black and yellow pigments called melanin in both the front part and back part of your iris. If you have no melanin in the front part of your iris and some melanin in the back part, you have blue eyes. An increasing proportion of the yellow melanin, in combination with the black melanin, results in shades of colors between brown and blue, including green and hazel.
While what we are taught in high school biology is generally true, (brown eye genes are dominant over blue eye genes) because many genes are required to make each of the yellow and black pigments, there are ways to get brown or green eyed kids from blue eyed parents.
Also there are environmental factors that can increase brown iris pigmentation and change blue eyes into brown eyes, like that drug Latisse that grows eyelashes.