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Black eyes are dominant to orange eyes, and green skin is dominant to white skin. Sam, a MendAlien with black eyes and green skin, has a parent with orange eyes and white skin. Carole is a MendAlien with orange eyes and white skin. If Sam and Carole were to mate, the predicted phenotypic ratio of their offspring would be _____. Select one:

Respuesta :

The correct answer is explained below:

Explanation:

  • According to the given question,
  • For eye color, let the black color be represented by B allele and orange color be represented by b allele. Black is dominant over orange.
  • For skin color, let the green skin be represented by G allele and white skin be represented by g allele. Green is dominant over white.
  • The phenotype of Sam is black eyes and green skin so his genotype can be BBGG or BbGg. It is also said that one of his parents has phenotype orange eyes and white skin. That parent's genotype must be bbgg.
  • Hence, the genotype of Sam must be BbGg.
  • Carole has the phenotype of orange eyes and white skin. Her genotype would bbgg.
  • The gametes produced by Sam are: BG, Bg, bG, bg.
  • The gametes produced by Carole are: bg.
  • Mating them we get,

           BG                    Bg                   bG                       bg

bg      BbGg               Bbgg               bbGg                   bbgg

  (Black/ Green) (Black/ White) (Orange/Green)  (Orange/ White)

  • The genotypes and phenotypes (Eye color/ Skin color) obtained are represented above.
  • The phenotypes (Eye color/ Skin color) obtained are in the following ratio:

(Black/ Green) : (Black/ White) : (Orange/Green) : (Orange/ White) = 1 : 1 : 1 : 1