contestada

The coat color in mink is controlled by two codominant alleles at a single locus. Red coat color is produced by the genotype R1R1, silver coat by the genotype R1R2, and platinum color by R2R2. White spotting of the coat is a recessive trait found with the genotype ss. Solid coat color is found with the S- genotype.
1. What is the expected phenotype distribution for the cross ssR1R2 × SsR2R2?
Express your answer as four numbers separated by colons.
2. If the cross ssR1R2 × SsR1R1 is made, what are the progeny phenotypes?
A. spotted platinum
B. spotted silver
C. spotted red
D. solid platinum
E. solid silver

Respuesta :

marianaegarciaperedo

In codominance, a phenotype expresses two alternative variants inherited from each parent. 1) expected phenotype distribution ⇒ 1:1:1:1. 2) progeny phenotypes: B. spotted silver, C. spotted red, E. solid silver.

Available data

  • coat color controlled by codominant alleles
  • Red coat color  ⇒  genotype R1R1
  • silver coat ⇒  R1R2
  • platinum color ⇒   R2R2
  • White spotting of the coat is a recessive trait ⇒   genotype ss
  • Solid coat color ⇒   S- genotype

What is codominance?

Refers to those cases in which a phenotype expresses two alternative variants inherited from each parent.

It is an additive expression of their parents' genes. Both alleles are equally expressed.

When two individuals, that are h0m0zyg0us and different for a trait, are crossed they produce heter0zyg0us individuals that express both parental phenotypes.

Cross 1

Parentals)  ssR1R2    ×      SsR2R2

Gametes)   sR1, sR1, sR2, sR2

                  SR2. SR2, sR2, sR2

Punnett square)        sR1           sR1           sR2          sR2

                   SR2    SsR1R2     SsR1R2    SsR2R2    SsR2R2

                   SR2    SsR1R2     SsR1R2    SsR2R2    SsR2R2

                    sR2    ssR1R2      ssR1R2    ssR2R2     ssR2R2

                    sR2    ssR1R2      ssR1R2     ssR2R2    ssR2R2

F1) Genotype

  • 4/16 individuals are expected to be SsR1R2
  • 4/16 individuals are expected to be SsR2R2
  • 4/16 individuals are expected to be ssR1R2
  • 4/16 individuals are expected to be ssR2R2

    Phenotype

  • 4/16 individuals are expected to have solid silver coat  
  • 4/16 individuals are expected to have solid platinum coat
  • 4/16 individuals are expected to have spotted silver coat
  • 4/16 individuals are expected to have spotted platinum coat

The expected phenotype distribution for the cross ssR1R2 × SsR2R2 is 4:4:4:4 or 1:1:1:1

Cross 2

Parentals)   ssR1R2 ×   SsR1R1

Gametes)  sR1, sR1, sR2. sR2

                 SR1, SR1, sR1, sR1

Punnett square)           sR1           sR1          sR2           sR2

                       SR1     SsR1R1     SsR1R1    SsR1R2     SsR1R2

                       SR1     SsR1R1     SsR1R1    SsR1R2     SsR1R2

                       sR1     ssR1R1       ssR1R1     ssR1R2    ssR1R2

                       sR1     ssR1R1       ssR1R1     ssR1R2    ssR1R2

F1) Genotype

  • 4/16 individuals are expected to be SsR1R1
  • 4/16 individuals are expected to be SsR1R2
  • 4/16 individuals are expected to be ssR1R1
  • 4/16 individuals are expected to be ssR1R2

    Phenotype

  • 4/16 individuals are expected to have solid red coat  
  • 4/16 individuals are expected to have solid silver coat
  • 4/16 individuals are expected to have spotted red coat
  • 4/16 individuals are expected to have spotted silver coat

The progeny phenotypes are

B. spotted silver

C. spotted red

E. solid silver

You can learn more about codominance at

https://brainly.com/question/14053639

https://brainly.com/question/3578928

Otras preguntas