• Question: Both parents have hazel eyes, how likely is it that their child will have hazel eyes according to genes?

    Asked by graciiebaybiie to Louise, Michaela, Sian, Steve, Yvette on 14 Jun 2010 in Categories: .
    • Photo: Louise Johnson

      Louise Johnson answered on 14 Jun 2010:

      The genetics of eye colour are pretty complicated. More than one gene is involved and the environment plays a part too. So it depends what the parents’ genes are!

      So: Hazel eyed people are often genotype bbGG (that means they haven’t got the B gene for brown eyes or the g gene for blue eyes) and if both parents are bbGG then all their children will be too. BUT they won’t necessarily have hazel eyes because people with those genes can have darker or lighter eyes depending on the environment. See, I warned you it was complicated…

      tl;dr version: I don’t know

    • Photo: Michaela Livingstone

      Michaela Livingstone answered on 14 Jun 2010:

      Ah, interesting question. SO the simple theory is that you have a gene and that gene can exist in different variations, called alleles. So for example with eye colour, the eye colour gene would have a brown version or allele, a blue allele, a green allele, a hazel allele, etc. Also there are ‘relationships’ between these alleles, so one might be stronger or ‘dominant’ – the technical word, over the others. Some might be weaker or ‘recessive’. So depending on how strong or weak the hazel version is you can work out the probability of their child having hazel eyes. At the end of the day it would be AT LEAST a 50/50 chance theoretically. Kind of hard to explain why without drawing a picture. Hope that makes sense! Though as Louise said, it’s complicated and I think more than one gene actually plays a role in eye colour!

      In reality though all sorts of weird things can mean that they might have a blue eyed kid! Go figure ey 🙂

    • Photo: Yvette Wilson

      Yvette Wilson answered on 14 Jun 2010:

      I thought that would be easy to answer, but had a quick look on wikipedia (http://en.wikipedia.org/wiki/Eye_color) and it seems that because there are many different genes involved in eye colour its not so easy to predict. Sorry – don’t know too much about this at the moment!

    • Photo: Steven Kiddle

      Steven Kiddle answered on 14 Jun 2010:

      Im afraid i don’t know. Genetics can be really complex, many things like eye colour aren’t always controlled by single genes and so its hard to say.

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