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Croaking in frogs is controlled by one gene with a pair of alleles - dominant uttering (R) and recessive muttering (r). Eye color is inherited by epistatic interaction of two genes with the following possible phenotypes: A_B_ - blue eyes; A_bb - purple eyes and aaB_ or aabb - green eyes. The frog geneticist mated two purple utteres with the following results: Part A 9/16 purple, utterers 3/16 purple, mutterers 3/16 green. utterers 1/16 green. mutterers What were the genotypes of the parents? a. AabbRr x AaBbRr b. AabbRr x AAbbRr c. AabbRr x AabbRr d. AAbbRr x AaBbRr e. AabbRr x Aabbrr f. AaBbrr x AabbRr

Respuesta :

marianaegarciaperedo

Answer:

The cross with the correct genotypes of the parents is AabbRr x AabbRr -option C-.

Explanation:

Available data:

  • Dominant uttering (R) and recessive muttering (r)
  • Eye color is inherited by epistatic interaction
  • A_B_: blue eyes; A_bb: purple eyes; aaB_ or aabb: green eyes.

Cross)                 AabbRr     x    AabbRr

Gametes)    RAb   Rab   rAb   rab

                    RAb   Rab   rAb   rab

Punnet Square)              RAb            Rab            rAb             rab

                           RAb    RRAAbb    RRAabb     RrAAbb    RrAabb

                           Rab     RRAabb     RRaabb     RrAabb     Rraabb

                           rAb     RrAAbb      RrAabb      rrAAbb     rrAabb

                          rab      RrAabb       Rraabb      rrAabb      rraabb

Note) Each parent has two copies of each gamete, which means that these results should be muliplied by four. But in oder to make it understandable, I resumed it, and just put half of the gametes.

Progeny phenotypes) 9/16 purple, utterers R-A-bb

                                    3/16 purple, mutterers rrA-bb

                                    3/16 green, utterers  R-aabb

                                    1/16 green, mutterers  rraabb

Option a. AabbRr x AaBbRr: Incorrect, as one of the parents has a genotype for blue eyes, A-B-

Option b. AabbRr x AAbbRr: Incorrect, as one of the parents is homozygote for A, so there would not be any green descendant.

Option c. AabbRr x AabbRr: Correct

Option d. AAbbRr x AaBbRr: Incorrect, as one of the parents has a genotype for blue eyes, A-B-

Option e. AabbRr x Aabbrr: Incorrect, as one of the parents is muttering, rr

Option f. AaBbrr x AabbRr: Incorrect, as one of the parents is muttering, rr and has a genotype for blue eyes, A-B-                        

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