Originally Posted by mama2mygirl
I went to see a genetic couselor when pregnant with my dd2. She said it was much more complicated than that. I was talking to her about the charts when learn in high school. You know, Dominant Domminant + Dominant Recessive can never be blue eyed. Or Recessive Recessive + Recessive Recessive always = blue. She said that just a really simplified version.
For what it's worth, my eyes are blue grey and my dh's are light brown. He is Peruvian and chinese and has one grandma who was green eyed. My dd1 has green eyes. Sometimes they look blue but mostly they are green. They are never brown and never have looked brown. I think my one-year-old is going to have the same color but I'm not sure.
Well, yeah, eye color isn't monovalent, but the little tool helps for most people-especially those with little or no genetic background. Human eye color is controlled by 3 or more genes: Blue/brown, blue/green, and central brown (possibly more, but only 3 have been proven for sure, although likely 6 or more are involved for all the subtle coloring) with 2 possible alleles each. Those different alleles of the genes interact with each other to deposit melanin (coloring) into the iris. There are also different genes for starbursts, spots, stripes, etc. So, there are 5 basic eye colors, with variation, making it appear to be like a continuous possibility from very light blue to almost black in color. *most of these variations are in people of european ancestry*
There is also some linking with skin and hair color to eye colors, but that is way too complicated for me. However, the basic blue/green/brown system works for most people curious about possible children's colors (barring hazel and some grey colors). You won't know the specifics, but if you have blue and the father has blue, your kid will have blue almost 100% of the time.
Side note: my grandmother has one brown and one blue eye. The blue/brown coloring (except for subtleties of the color) occurs on one gene like an "on/off" switch. The beginning of this gene signals the eyes to have lots or little melanin. If there is a mutation on an eye that should be brown that keeps it from producing as much melanin as it is supposed to, it can show up
blue. That's what happened to my g-ma: she was supposed to have both brown eyes, and has a mutation in 1 that showed up blue. Another gene can sort of switch from brown to green/hazel, so 2 diff. eye colors aren't unheard of. And I think they're pretty cool.
(Disclaimer: some mild genetic diseases, in-womb trauma, and diseases can produce 2 different color eyes, but they usually look "off")