The genotype of f1 individuals in a tetrahybrid cross is aabbccdd. assuming independent assortment of these four genes, what are the probabilities that f2 offspring would have the following genotypes? show your work.
(1)aabbccdd.
(2) aabbccdd.
(3) aabbccdd.
(4) aabbccdd

The ratio of genotypes can be determined by examining the Punnett square.
Let's find what each pair stands for in terms of ratios:
aa = 1/4
bb = 1/4
cc = 1/4
dd=1/4
Aa = 1/2
Bb = 1/2
hence, 

1. aabbccdd = 1/4 x 1/4 x 1/4 x 1/4
                     =  1/256
2. AaBbCcDd = 1/2 x 1/2 x 1/2 x 1/2 
                       =  1/16
3. AABBCCDD = 1/4 x 1/4 x 1/4 x 1/4 
                         = 1/2564.
4. AaBBccDd = 1/2 x 1/4 x 1/4 x 1/2 
                      = 1/64

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