Please answer all questions. ALL questions. Please and thanks. Please answer all

Question

Please answer all questions. ALL questions. Please and thanks. Please answer all questions. ALL questions. Please and thanks. 6. In guinea pigs, coat color can be white, cream or yellow. Of these three phenotypes, only the cream-colored guinea pigs never breed true. When two cream-colored guinea pigs are crossed, ya are yellow, are cream and are white. A cream-colored guinea pig by white guinea cross yields % cream and '% white offspring. a. b. c. How many genes control coat color in the guinea pig? Give the mode of inheritance of coat color in the guinea pig. Why is it impossible for cream-colored guinea pigs to breed true? 7. The Manx trait in cats results in shortened or absent tails. Cats that do not have the Manx trait developed full length or normal tails. A breeder crosses two cats with the Manx trait, and observes the following in the Fi generation: 266 Manx tail 134 Normal tail a. What type of specific inheritance pattern do these data indicate? b. What is the genotype of Manx cat? 8. In the pearl millet plant, color is determined by three alleles: Rp (red), Rp (purple) rp. Based on this information answer the following questions: a. Give the number of possible genotypes that can result from these alleles. b. Give the expected phenotypes and ratios expected from the following cross 9. In the population of Bosmina longiristris (pictured at right), there are two types of Bosmina, the following genotypes were determined using biochemical methods: Genotypes Number phosphoglucose isomerases resulting from the two alleles, S' and S'. In 176 s's s's s' s 38 134 a. Calculate the genotypic frequency for the S S individuals in the b. Calculate the frequency of the S allele in this population using all the population. data.

Explanation / Answer

6. color coat of guinea pig:

Let’s take the following genotype as the color coat

          CC for yellow

          Cc for cream

           cc for white

When cream-coloured is crossed with cream-coloured

                                 Cc×Cc

                      

C

c

C

CC

1/4

Cc

1/4

c

Cc

1/4

Cc

1/4

So, CC is ¼, Cc is ½ and cc is ½.

When cream-coloured is crossed with white colored

              Cc×cc

c

c

C

Cc

1/4

Cc

1/4

c

Cc

1/4

Cc

1/4

So, Cc is ½ and cc is ½

On basis of our cross done above we can answer following:

a. One gene controls the color coat. It has two alleles.

b. Mode of inheritance is incomplete dominance

c. Cream-colored guinea pig do not breed true because they have heterozygous allele and only homozygous allele can give true breed results.

7. When two cats with Manx tail are breed, they give 266 Manx tail and 134 normal tail cats

                                    Total number of cats= 266+134

                                                                          = 400

                                       Ratio of manx tail cat= 266/400

                                                                            =3/4 approx.

                                        The ratio of normal tail cat= 134/400

                                                                                 =1/4 approx

         Since if the Manx tail cat would be homozygous then F1 should have all Manx tail cat

But F1 has both Manx and normal tail cat, so Manx tail cat must have heterozygous genes

a. This shows autosomal dominance inheritance

b. The genotype of Manx tail is heterozygous.

                       

                                  

  

C

c

C

CC

1/4

Cc

1/4

c

Cc

1/4

Cc

1/4

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