Why does my brother have 20/20 vision when my parents and I don't?!
Question: What is different about our--my mother, my dad, and me--eyes that causes us to need glasses? Or what is different about my brother's eyes that causes him not to need glasses?
Answers: What is different about our--my mother, my dad, and me--eyes that causes us to need glasses? Or what is different about my brother's eyes that causes him not to need glasses?
There probably isn't anything different about your brother's eyes. The way genes for eyesight work is that imperfect eyesight is dominant and perfect eyesight is recessive. this means that if one of your parents pass down a gene for bad eyesight you will have bad eyesight.
So let's just say that your dad and mom both have one gene for bad eyesight (E) and one for good eyesight (e). Either, one of them passed down the gene for bad eyesight, and one for good, (in which case you would have imperfect eyesight), or they both passed down "big E's". Your brother lucked out in heredity and got two genes for perfect eyesight...
It's all hereditary
20/20 vision has to a recessive trait then. So for instance, your dad's mom has 20/20, but your dad's dad has 40/20. So your dad HAS 40/20 and recieved 20/20 as a recessive trait, which then passed onto your brother. Your brother may have recessive 40/20...
They say it skips a generation, but I'm not sure if I believe that.
You might want to post this question again in the "optical" category. (also under "Health.) There are a lot of optometrists and ophthalmologists over there. Please be thankful that you have good vision!! Appreciate it every day! :)
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