Expert: Walter Hintz - 10/11/2011

Question
QUESTION: I have hazel eyes.  Largely green (kind of an aqua) with a golden orange center.  Both of my siblings have dark brown eyes.  My mother (half Mexican) has brown.  My father has what HE considers brown, but I'd say hazel...but far darker than mine.  They are light brown with an olive green border around them. My mother's mom has blue eyes, but with a goldish hazely center...but very apparently blue nonetheless.  Her father has brown eyes.  My father's mom has blue eyes...and I'm not sure about his father.   I am married to a blue eyed man.  His mother has brown eyes, and his father blue.  He has a sister with hazely brown eyes.  My question is what possible eye colors could our children have?  I've always been confused on the genotype of hazel eyes.

ANSWER: Hi Samantha
Hair, skin and eye colors all depend upon the amount of melanin and the production of melanin is controlled by genes.  While most traits involve a single pair of genes pigmentation involves multiple genes which allows for degrees of darkness. So we do not have either dark brown eyes or light blue eyes, Instead we have varying shades like dark brown, light brown and hazel as well as shades of blue or green..
 Now as to your question. First of all remember that darker pigments dominate over lighter pigments.  Your mother and your father have dark eyes but you maternal grand mother has passed on genes for blue. You mentioned green with your eyes so you must have genes for lighter colors. Your husband has blue eyes. There is a good chance that your children will have light eyes,either lighter shades of brown or even blue eyes.

---------- FOLLOW-UP ----------

QUESTION: Thanks for so much for your answer.  I did figure it would at least be possible to have a blue eyed baby because since I do not have brown eyes I must not have gotten my mother's blue eye gene and not her brown, correct?  So, having moderate amounts of melanin could still give my children light brown eyes even though I don't have a gene for brown eyes?  I'm sorry, I'm confused.  I am 1/4 Mexican and olive/tan, but with light brown hair, almost dirty blonde. My husband is very very pale.  So it's likely my children will also be?  Will having less melanin than I do increase their chances for lighter eyes?  I never understand how green and hazel work.  Only how blue and brown work.

Answer
It is quite likely that you are carrying genes for both light and dark pigmentation. Remember I told you that eye color depends upon not one pair of genes but three pair. You and your husband both carry recessive genes and it is quite that you children will have light pigmentation. Less melanin means lighter coloration