dihybrid cross

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simmonsk
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dihybrid cross

Post by simmonsk » Sun Oct 28, 2007 8:38 pm

I thought I understood dihybrid crosses... and now that I'm working on one I'm confusing myself!
How do I know if the parent is heterozygous or homozygous?
The problem I am working on:
Mating a long-eared(dominant) non-drooling(dominant) Bassett hound with a short-eared(recessive) drooling(recessive) Bassett hound. The F1 are all long-eared(dominant) droolers(recessive). What are the F2 offspring?

I understand that the second parent is lldd and that the first parent is LLD? but what is the second D? I know that it has to do with knowing what all of the F1 generation is... but I don't remember... help?

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mith
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Post by mith » Sun Oct 28, 2007 9:59 pm

Your F1 is droolers which means they're fully recessive. Which means there is a drooler gene from each parent. Thus the parents are?
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simmonsk
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Post by simmonsk » Sun Oct 28, 2007 11:29 pm

oh. duh. that means the other parent must have the recessive drooler gene too. so the genotype is Dd, correct?

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Post by Ultrashogun » Tue Oct 30, 2007 6:41 pm

simmonsk wrote:oh. duh. that means the other parent must have the recessive drooler gene too. so the genotype is Dd, correct?


Yeah but if it were Dd x dd then not all the F1 would be droolers.

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Post by simmonsk » Tue Oct 30, 2007 8:05 pm

I figured it out... thanks for the help though! :)

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