The mouse with dark eyes carries the genetic trait for dark pigment (melanin, perhaps?), which is dominant over the albino genes (double recessive for lack of dark pigment)?
Genetics Teaser
by TD 14 Replies latest jw friends
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TD
I think cofty knows the answer, but I muddied the question a little bit with the 90% observation.
Okay, one of the white mice is albino (Pink eyes) and the other is normal white mouse (Brown eyes)
Albinism prevents whatever color the mouse would normally have been from being expressed, (Melanocytes are non-functioning) but the genetic information is all still there and is inherited by the offspring.
So when you cross an albino mouse with a normal mouse the results are unpredictable. If the albino would normally have been solid black, most of the offspring will be black, since black is dominant.
Using the Punnett squares we were taught in school you would think that 75% of the offspring would be black and 25% would be white, but coat color is actually controlled by several different alleles. In this pairing, none of the offspring are ever white. Most are black and one or two out of each litter are either tan or grey.
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FlyingHighNow
Scully and I both answered what you said, each in our simpler ways. The dark eyes in the one mouse are the key to answer your question.
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TD
This was a shameless trick question and it was nice that you all humored me.
It's actually the mouse with pink eyes (The albino) who is the source of the dark colors in the offspring
Brown eyes on a white mouse tell you that white is the true genetic color
Pink eyes on an albino tell you that white is probably not the true genetic color.
The best way to tell the true genetic color of an albino mouse is to breed it with a normal white mouse.
In this case, it's obvious that the albino is really a black mouse.
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Scully
In this case, it's obvious that the albino is really a black mouse.
Well, of course it's perfectly obvious.