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Probablility of blue eyes
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What is the probability of a child having blue eyes at birth when the parents have " brown and blue " eyes?
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All babies are born with blue eyes ~ just varying shades. My brother has brown eyes, and at birth his eyes were a very deep blue..more of a navy colour.
Mr Pippa has brown eyes & I have blue. Our daughters have blue eyes.
It also depends on your own parents eye colours as to the eventuality of your childs eye colour. Dominant genes are a funny thing.
Mr Pippa has brown eyes & I have blue. Our daughters have blue eyes.
It also depends on your own parents eye colours as to the eventuality of your childs eye colour. Dominant genes are a funny thing.
Most babies are born with blue eyes, the transformation has to do with the protein melanin. Melanin is a brownish pigment that adds colour to hair, eyes, and skin. At the time babies are born, melanin hasn't yet been "deposited" in the eyes' iris. Hence, they appear blue.
After about six months, eyes change colour depending on the amount of melanin. If there is a lot of it, the eyes will turn brown or black. If there is little, they'll stay blue. And if there is no melanin (albinism), then the eyes may appear pink.
Research shows that where one parent has blue eyes and the other has brown eyes, that the child has a 50% chance of having blue and 50% chance of brown. Where the parent with the blue eyes has a lesser blue colour, then the brown will be dominant. For example with brown and blue/green eyed parents, the odds are that the child has 50% probability of brown eyes and 25% probability of green eyes and 25% probability of blue eyes (or 50% blue/green). About half of the children with brown eyes will carry the Green allele for the gey gene (common gene for eye colour ), and the other half will carry the blue allele, so their children may have blue, green or brown eyes.
After about six months, eyes change colour depending on the amount of melanin. If there is a lot of it, the eyes will turn brown or black. If there is little, they'll stay blue. And if there is no melanin (albinism), then the eyes may appear pink.
Research shows that where one parent has blue eyes and the other has brown eyes, that the child has a 50% chance of having blue and 50% chance of brown. Where the parent with the blue eyes has a lesser blue colour, then the brown will be dominant. For example with brown and blue/green eyed parents, the odds are that the child has 50% probability of brown eyes and 25% probability of green eyes and 25% probability of blue eyes (or 50% blue/green). About half of the children with brown eyes will carry the Green allele for the gey gene (common gene for eye colour ), and the other half will carry the blue allele, so their children may have blue, green or brown eyes.
Try here...
http://museum.thetech.org/ugenetics/eyeCalc/ey ecalculator.html
it works out the most likely outcome.
http://museum.thetech.org/ugenetics/eyeCalc/ey ecalculator.html
it works out the most likely outcome.
The classical view of this inheritance is as follows:
Blue (b) is recessive to brown (B).
The blue-eyes parent must have inherited a (b) gene from both parents and be (bb).
The brown eyed parent will be either (BB) or (Bb).
If the brown eyed parent is (BB) then (BB) crossed with (bb) will always give (Bb) offspring with brown eyes, i.e. 100% certainty.
If the brown eyed parent is (Bb) then there is a 50% chance of the offspring being (Bb = brown) and 50% chance of being (bb = blue)
So it really depends upon the chances of the brown-eyed parent being (BB) or (Bb) and that will depend on their parents and grandparents etc.
The overall chances of the child having brown eyes will therefore lie somewhere between 50% and 100%.
Unfortunately, the classical view is a little over-simplified as eye colour is not determined by a single gene by the abobe is a good indication of what is likely.
Blue (b) is recessive to brown (B).
The blue-eyes parent must have inherited a (b) gene from both parents and be (bb).
The brown eyed parent will be either (BB) or (Bb).
If the brown eyed parent is (BB) then (BB) crossed with (bb) will always give (Bb) offspring with brown eyes, i.e. 100% certainty.
If the brown eyed parent is (Bb) then there is a 50% chance of the offspring being (Bb = brown) and 50% chance of being (bb = blue)
So it really depends upon the chances of the brown-eyed parent being (BB) or (Bb) and that will depend on their parents and grandparents etc.
The overall chances of the child having brown eyes will therefore lie somewhere between 50% and 100%.
Unfortunately, the classical view is a little over-simplified as eye colour is not determined by a single gene by the abobe is a good indication of what is likely.
heres my twopence!!!
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