Originally posted by serbsta
reply to post by Monts
Originally posted by Monts
The only way your guaranteed to have a child with blue eyes is if both your parents have blue eyes.
That can't be right. Neither of my parents, nor my grandparents have blue eyes, yet I do. I don't know who taught you that but it certainly doesn't
comply with my situation.
There can be some variance and exceptions, but the way I was taught was that it was a recessive gene, and can be summed up by this graph:
In this case, capital R represents dominant gene (brown eyes) and lower case r represents recessive gene (blue eyes). As long as the dominant gene is
present in offspring, (brown eye), than they will have brown eyes. The person with RR had two dominant brown eye genes received from his/her parents,
while the other had two recessive rr blue eye genes received from their parents. The first had brown eyes, while the second has blue, and as a result,
all children have brown eyes, but at the same time carry the recessive gene.
Therefore it is 100% guaranteed children will have brown eyes, but will carry the recessive blue-eyed gene.If these children partner with another RR
brown eyes, 50% will have RR dominant brown eye gene, while 50% will have brown eye dominant Rr gene with recessive blue eyes. All will have brown
If an Rr partners with an rr, then 50% will be Rr, with brown eyes, while 50% will be rr with blue eyes. So you need to have both recessive traits in
order to have blue eyes.
If two people with blue eyes become partnered, then their children will all have 100% rr, as their parents have to have both recessive genes in order
for them to have blue eyes. This is assuming of course, if blue eyes/brown eyes are the only genetic eye-color traits in the gene pool.
This is very simplified of course, and as in all biology, there are always exceptions and freaks of nature. And the percentages represent theoretical
ones, because nature is random by nature.
So your parents/grandparents never had blue eyes, however they could have been carrying the recessive blue-eyed trait with them, which would mean that
theoretically they would both be Rr's, with dominant brown eyes gene and recessive blue-eyed gene.