On a newly discovered island in the South Pacific, a geneticist found two distin

Question

On a newly discovered island in the South Pacific, a geneticist found two distinct pure?breeding populations of frogs: Strain 1: the frogs have purple eyes and croak by uttering rib?it rib?it (utterers) Strain 2: the frogs have green eyes and croak by muttering knee?deep knee? deep (mutterers) She mated frogs from the two lines, producing F1 frogs that were all utterers with blue eyes.

A large F2 generation then yielded the following ratio: 27/64 blue, utterers 12/64 green, utterers 9/64 blue, mutterers 9/64 purple, utterers 4/64 green, mutterers 3/64 purple, mutterers

a. How many total gene pairs are involved in the inheritance of both eye colour and croaking? Justify your answer.

b. Of these, how many control eye colour and how many control croaking?

c. Assign gene symbols for all the gene pairs and give the genotypes of the Parental, F1 and the genotypes for all of the six F2 phenotypes.

d. After many years, the geneticist isolated true?breeding lines of all six F2 phenotypes. Give the F1 and F2 phenotypic ratios of a cross between a blue, mutterer and a purple, utterer.

Explanation / Answer

27/64 blue, utterers

12/64 green, utterers

9/64 blue, mutterers

9/64 purple, utterers

4/64 green, mutterers

3/64 purple, mutterers

a. How many total gene pairs are involved in the inheritance of both eye colour and croaking? Justify your answer.

here, colour of the frog's eye is controlled by two genes pairs or total four alleles, while

its croak is controlled by one gene pair or two alleles.

Total= 3 gene pairs------------------answer

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b. Of these, how many control eye colour and how many control croaking?

4 involve color, 2 involve croak

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c. Assign gene symbols for all the gene pairs and give the genotypes of the Parental, F1 and the genotypes for all of the six F2 phenotypes.

B/-E/-U/- is blue utterer

B/-eeU/-is green utterer

B/-E/-uu is blue mutterer

bbE/-U/- is purple utterer

bbeeuuis green mutterer

bbE/-uu is purple mutterer

It is epistatic recessive

P1=bbEEUU by BBeeuu

F1=BbEeUu

F2=

27/64 blue-eyed, uttererB/-E/-U/-

12/64 green-eyed, uttererB/-eeU/-

9/64 blue-eyed, muttererB/-E/-uu

9/64 purple-eyed, uttererbbE/-U/-

4/64 green-eyed, muttererbbeeuu

3/64 purple-eyed, muttererbbE/-uu

d. After many years, the geneticist isolated true?breeding lines of all six F2 phenotypes. Give the F1 and F2 phenotypic ratios of a cross between a blue, mutterer and a purple, utterer

P1=bbEEUU by BBEEuu, purple uttering by green muttering

-F1=BbEEUu green uttering

-F2=

9-B/-EEU/- Green utterer

3-B/-EEuu Green Mutterer

3-bbEEU/- Purple utterer

1-bbEEuu purple mtterer

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