Posted by:
hhmoore
at Sat Jun 25 22:43:14 2005 [ Report Abuse ] [ Email Message ] [ Show All Posts by hhmoore ]
To understand why, take a look at these examoles. As already stated, albinism is a simple recessive trait. I will indicate the trait with a lower case "a". normal with a capital "A". A het for albino carries the trait but looks normal. It would therefore be represented as "Aa". A visible albino would be "aa". So for your scenario, albino x het would be calculated in a punnett square, as below A a a Aa aa In this case, half of the offspring are Aa a Aa aa (hets) and half are aa (albino)
for albino x albino
a a a aa aa All the offspring are aa (albino) a aa aa
for albino x normal
A A a Aa Aa All the offspring are Aa (hets) a Aa Aa
The percent hets (66%, 50%) refers to the likelihood that a given offspring is carrying the recessive trait. the lower the number, the less likely it is that it will prove out. this is because if you are not working with obvious morphs, or 100% hets, things get a little more involved. for example: het x normal
A a A AA Aa half are normals, half are hets. you can't A AA Aa tell them apart by looking at them, so they are marketed as 50% hets.
A het X a het looks like this:
A a A AA Aa In this case 1/4 are visual albino (aa), 1/4 a Aa aa are normal, and 2/4 are hets. take the visual morphs out of the picture and you see that 2/3 are het...marketed as 66% het
Hope this helped
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