Does anyone know about genetics in eye colour?
Eye color is not caused by a single gene. If it were, then there would only be two varieties of eye color…. for exmple: “Gene A’s” dominant color (dominant allele) and a “Gene A’s recessive color (recessive allele). Because of this, you cannot predict or plan your child’s eye color that simply. A punnet square isn’t going to do it. You can look at probabilities. Your parents were both carrying the recessive blue gene…. you just happened to get a combination of these from BOTH parents. Another child from them may not get this combination again.
There are two primary genes involved in eye color: B and G Each person has two alleles for each gene. So, you can be BBGG or BbGG or bbGg or Bbgg, etc. If you are dominant at the B gene (so BB or Bb) then you have brown eyes and it doesn’t matter what you are at the G gene. But, if you are homozygous recessive at the B gene (bb) and dominant at the G gene (Gg or GG), then you have green eyes. To have blue eyes you are homozygous recessive at both genes: bbgg. So, if you have blue eyes, then you give your baby a b and a g allele. If the father has brown eyes, all you really know about his genotype is that he has at least one B allele, but he could be: BBGG – all your children would have brown eyes BBGg – all your children would have brown eyes BBgg – all your children would have brown eyes BbGG – 50% chance of brown eyes, 50% chance of green in children BbGg – 50% chance of brown, 25% chance of green, 25% chance of blue Bbgg – 50% chance of brown, 50% chance of blue If the father has bl