Both my parents have brown eyes. My older and younger siblings have brown eyes. I have green eyes. Is this genetically possible? Back in 1962, this was questionable and led to family problems, which have long since been resolved.


Of course it is possible. Your parents obviously have two different allels for the eye color (heterozygous), one recessive for green/blue eyes and one dominant, for brown eyes, which is expressed in this case beacuse dominant allel determines eye color if present. You and your siblings have inherited one allel from each parent. Your siblings have inherited at least one dominant (brown) allel from one of the parents, so they have brown eyes as well. You have inherited recessive allels for green eyes from both of them (homozygous). The chance to inherit two recessive allels in this case were 25%. I hope this helped you a bit :)

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  • $\begingroup$ @TamaraSpipka do you have any reason to think that eye colour genetics is that simple? In fact it does not seem to be that easy Zhu et al. (2012) $\endgroup$ – Remi.b Feb 25 '18 at 17:06
  • $\begingroup$ There are at least three major effect QTL according to Mengel-From et al. 2009 $\endgroup$ – Remi.b Feb 25 '18 at 17:08
  • $\begingroup$ I agree with you that it is not that simple, especially because there are more complex eye colors besides clear brown, green or blue. But the color example in the question and the question itself were very simple: 'Is it possible?' and it was quite explicable in the simple way. Don't you agree with this? $\endgroup$ – Tamara Sipka Feb 25 '18 at 17:15
  • $\begingroup$ I would tend to agree it is possible (although I'd love to have a reference for it) but I disagree with the explanation provided. $\endgroup$ – Remi.b Feb 25 '18 at 17:20

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