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New Topic  
Anonymous sara5656
wrote...
A year ago
1) Which of the following scenarios best describes an epistatic gene?

a. Fur pattern is controlled by two genes such that one gene inhibits the expression of the other gene.

b. Mouse fur colours are expressed as a blend of the dominant black colour and the recessive white colour, resulting in a heterozygous brown colour.

c. Individuals with sickle cell anemia and carriers of the sickle cell allele have some resistance to malaria.

d. Chicken combs follow a dominance hierarchy whereby a walnut comb is the most dominant and a single comb is the least dominant.




2) SEE IMAGE ATTACHED PLEASE







3) If the P1 generation is a rose comb (RRpp) crossed with a pea comb (rrPP), which of the following represents the correct genotype and phenotype of the F1 offspring?

a.    Genotype     Phenotype
          RrPp              pea comb

b.   Genotype          Phenotype
         RrPp                walnut comb

c.  Genotype   Phenotype
       RRPP        walnut comb

d.  Genotype   Phenotype
       RRPP              Single comb








4) Which of the following represents the correct phenotypes of the F2 offspring?

a.    Phenotype               
    Single                 Walnut               Pea                  Rose
     1 / 16                     9 / 16               3 / 16                 3  / 16


b.    Phenotype
  Single                   Walnut                    Pea          Rose
   3 / 16                      1 / 16                    9 / 16          3 / 16


c.    Phenotype
  Single                  Walnut                       Pea             Rose
  3 / 16                   9 / 16                       1/ 16            3  / 16


d.   Phenotype
  Single                 Walnut                        Pea                 Rose
   9 /  16                   3 / 16                      3 / 16                  1 /  16









5) The Labrador Retriever’s coat colours are black, yellow, and chocolate.

Yellow is produced by the presence of a recessive epistatic gene, which has the effect of masking the black and chocolate colour genes. Black (B) is dominant to chocolate (b).

Therefore, the possible genotypes and corresponding phenotypes are:

Phenotype                                Possible Genotypes

Black                                                    G__B__

Brown                                                   G__bb

Yellow                                                    gg__

Predict the percentage of offspring that would be black in colour for each of the following crosses. Record your answer as a whole number.

Cross:                     GgBb   X   GgBB                                                                  GGBb      X     GGBb

Percentage         
of
Offspring:                    Answer %                                                                                    Answer %       














6) SEE IMAGE TWO ATTACHED PLEASE
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wrote...
Staff Member
A year ago
1) Which of the following scenarios best describes an epistatic gene?

a. Fur pattern is controlled by two genes such that one gene inhibits the expression of the other gene.

b. Mouse fur colours are expressed as a blend of the dominant black colour and the recessive white colour, resulting in a heterozygous brown colour.

c. Individuals with sickle cell anemia and carriers of the sickle cell allele have some resistance to malaria.

d. Chicken combs follow a dominance hierarchy whereby a walnut comb is the most dominant and a single comb is the least dominant.

3) If the P1 generation is a rose comb (RRpp) crossed with a pea comb (rrPP), which of the following represents the correct genotype and phenotype of the F1 offspring?

a.    Genotype     Phenotype
          RrPp              pea comb

b.   Genotype          Phenotype
         RrPp                walnut comb


c.  Genotype   Phenotype
       RRPP        walnut comb

d.  Genotype   Phenotype
       RRPP              Single comb

4) Which of the following represents the correct phenotypes of the F2 offspring?

a.    Phenotype               
    Single                 Walnut               Pea                  Rose
     1 / 16                     9 / 16               3 / 16                 3  / 16



b.    Phenotype
  Single                   Walnut                    Pea          Rose
   3 / 16                      1 / 16                    9 / 16          3 / 16


c.    Phenotype
  Single                  Walnut                       Pea             Rose
  3 / 16                   9 / 16                       1/ 16            3  / 16


d.   Phenotype
  Single                 Walnut                        Pea                 Rose
   9 /  16                   3 / 16                      3 / 16                  1 /  16

Quote
5) The Labrador Retriever’s coat colours are black, yellow, and chocolate.

Yellow is produced by the presence of a recessive epistatic gene, which has the effect of masking the black and chocolate colour genes. Black (B) is dominant to chocolate (b).

Therefore, the possible genotypes and corresponding phenotypes are:

Phenotype                                Possible Genotypes

Black                                                    G__B__

Brown                                                   G__bb

Yellow                                                    gg__

Predict the percentage of offspring that would be black in colour for each of the following crosses. Record your answer as a whole number.

Cross:                     GgBb   X   GgBB                                                                  GGBb      X     GGBb

Percentage         
of
Offspring:                    Answer %                                                                                    Answer %

Epistasis is a phenomena in genetics where the expression of one gene is affected by the expression of one or more independently inherited genes. Epistatic gene is a gene that determines whether or not a trait will be expressed.




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Anonymous Author
wrote...
A year ago
thanks
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