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F1 and F2 generations: aa bb (mutant) x AA BB

You cross an aa bb mutant plant with an AA BB wild type. What would the F2 segregation ratio be (wild type to mutant) if:

a.) both mutations, a and b, were recessive?
b.) both mutations were dominant?
c.) one mutation was dominant and one recessive?

(assume both mutations are required for the mutant phenotype)
(assume the genes are not linked)

Solution Preview

The F1 generation would be 100% AaBb.
The F2 cross would be between F1 siblings:
AaBb X AaBb
The possible gametes are: AB Ab aB ab
(see attached file for Punnet square; note that Arabidopsis nomenclature is ...