probability and blood group question help

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spoog74

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Can someone help me with this probability genetics question?
two organisms contain the genotype XxYy. If random recombination and independent assortment are assumed, what probability would there be to phenotypically express the dominant allele of the second gene and the recessive allele of the first gene ?


How would one go about doing this? It seems easy at first but i dont know where to start. The question is a bit vague, what do they mean by PHENOTYPICALLY, just expressing the dominant allele?
 
Can someone help me with this probability genetics question?
two organisms contain the genotype XxYy. If random recombination and independent assortment are assumed, what probability would there be to phenotypically express the dominant allele of the second gene and the recessive allele of the first gene ?


How would one go about doing this? It seems easy at first but i dont know where to start. The question is a bit vague, what do they mean by PHENOTYPICALLY, just expressing the dominant allele?

http://i1136.photobucket.com/albums/n488/Jab1113/WP_000323.jpg
 
??

can you please explain your reasoning?

The recessive allele of the first will only be expressed if it's xx, which is 1 out of the 4 possible combinations. The dominant of the second will be expressed anytime there's a big Y, so 3 out of the 4. If two events are independent, then the joint probability is the product of the probabilities of each of the events. 1/4 * 3/4 = 3/16
 
Just a thought...why cant we do this simply by knowing the ratio of dihybrid cross - 9:3:3:1

where,

9/16 = Dominant of both
3/16 = Dominant of 1st and recessive of 2nd
3/16 = Dominant of 2nd and recessive of 1st
1/16 = Recessive of both...

Any issue with using this..
 
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