Question about breeding, CAS, and genetics
toad:
Is it possible that eye colour also has penetrance issues?
So it's not necessarily that the milk man is the parent, but more that Daddy (or Mummy) has a brown gene that hasn't shown up, but does manage to work in the child.
Zazazu:
That's what I had heard, that there is a possibility that someone can have the genes for brown eyes, but display blue because the proteins are somehow blocked by some other condition. So a mom could be Bb, displaying blue due to the proteins being blocked, with the father bb and displaying blue of course. Child inherits Bb.
AuKestrel:
Quote from: BastDawn on 2008 August 01, 03:57:11
Research is interesting!
Indeed!
Almost all of the examples cited, however, have to do with genetic mutations, "gene swapping" or fetal damage during pregnancy. Because of this, I am thinking the possibility of two blue eyed parents having a brown eyed baby because of an incompletely expressed gene is more uncommon than the other causes.
But you're right and I was wrong: the question, can two blue eyed parents have a brown eyed child, can be answered "yes." :)
AuKestrel:
Quote from: Count Four on 2008 August 01, 05:23:03
My mother has green eyes, brown hair, my father has blue eyes, light brown hair. Between them, they produced three brunettes, three blondes (hair remains blonde in adulthood), one redhead, and two ash blondes. All of us except the redhead started out with blonde hair as kids.
Amongus are seven with blue eyes, one with green eyes, and one with brown eyes--and she's one of the colorfast blondes.
So it can happen that two people with 'recessive color' eyes can have a brown eyed kid. But they only managed it one in nine.
That would surprise me less than two blue eyed parents having a brown eyed child, because while green is dominant over blue and brown is dominant over green, green still indicates the presence of melanin and blue is still the absence of melanin. So if there are enough polygenes piling onto the pigmentation (the way they do in the rufus gene in red cats) - which I've always thought was one possible explanation for the great variations in eye colour - then I can see that green could be 'hiding" brown.
At any rate, yes, it is possible - I was wrong.
gethane:
This conversation has surely turned interesting. And it's such a relief when someone can in a good-natured way say "I was wrong" instead of maintaining an answer or becoming abusive, especially on the internets ;) So props.
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