phenotypes, genotypes, etc.

Genetics as it applies to evolution, molecular biology, and medical aspects.

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microwaveable
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phenotypes, genotypes, etc.

Post by microwaveable » Sun Jan 13, 2008 11:57 pm

very strange and puzzling questions - simple explanation would be immensely helpful! these questions are directly taken, no editing. what I really don't understand is how to list the different genotypes and phenotypes (is it just like Aa, AA, aA, aB, AB, etc.?)

1 - An ugggggggly guy marries a gorgeous girl (ugly is dominant). He is homozygous for ugh! She is homozygous for goooooood looking. How many good looking kids will there be in the F1 generation? List genotypes and phenotypes.

2 - Fat fingers is dominant over skinny fingers. What would be the genotypic and phenotypic ratios of a cross between a heterozygous fat-fingered person and a skinny-fingered person?

3 - Roaches either have the killer instinct, which is dominant, or the peace marcher instinct, which is recessive. What parent genotypes would produce all killer roaches? What parent genotypes would produce all peace marcher roaches?

thank you!

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MrMistery
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Post by MrMistery » Mon Jan 14, 2008 12:42 am

i'll do the first one for you - it is up to you to apply the method to the other two. These are genetics questions as easy as possible

So, let B be the gene for beauty
BB - homozygous dominant(ugly)
bb - homozygous recessive(gorgeous)
Bb - heterozygous(ugly)

BB x bb => Bb
In F1 all children will have Bb genotype, so all of them are ugly.
"As a biologist, I firmly believe that when you're dead, you're dead. Except for what you live behind in history. That's the only afterlife" - J. Craig Venter

microwaveable
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Post by microwaveable » Mon Jan 14, 2008 1:12 am

:O wow, that really was simple. I feel really stupid now, haha.

thanks a lot!

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