In rats, the P gene allele for pigmentation (P) is dominant to the allele for albinism (p). The B gene allele for black pigmentation (B) is dominant to the allele for cream pigmentation (b). The pp homozygous recessive genotype is epistatic to any allele combination at gene B. Predict the phenotypic ratio of the F2 progeny of a parental cross between a pure-breeding black rat and an albino that is also homozygous for cream.

A) 1 black: 2 cream: 1 albino
B) 9 black: 3 cream: 4 albino
C) 9 black: 7 albino
D) 12 black: 3 cream: 1 albino
E) 15 black: 1 albino


B) 9 black: 3 cream: 4 albino

Biology & Microbiology

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