In guinea pigs, the allele for black fur(B) is dominant over the allele for
brown fur(b), and the allele for short fur (F) is dominant over the allele
for long fur(f). What is the expected phenotypic ratio for a BbFf x BbFf
cross?

The expected phenotype ratio is 9:3:3:1 for a BbFf x BbFf  cross.

Explanation:

Data given:

Black fur dominant = BB, short fur dominant FF

brown fur recessive = bb, long fur ff

genotype of parents:

BbFf   and BbFf

The cross between these two genotype of parents is shown in the below punnet square:

             BF          Bf              bF         bf

BF   BBFF       BBFf          BbFF      BbFf

Bf    BBFf        BBff            BbFf       Bbff

bF   BbFF       BbFf           bbFF       bbFf

bf     BbFf        Bbff           bbFf        bbff

phenotype ratio:

black fur and short guinea pig = 9

black and long fur = 3

brown and long fur = 3

brown and short fur-1

 The expected phenotypic ratio is 9:3:3:1

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