Predicted Phenotypic Ratio of MendAlien Offspring
Understanding MendAlien Genetics
Black eyes are dominant to orange eyes, and green skin is dominant to white skin. In the MendAlien species, these traits are controlled by two genes with specific alleles. Let's explore how these genetic principles apply to a particular scenario involving two MendAliens, Sam and Carole.
Scenario
Sam is a MendAlien with black eyes and green skin. Interestingly, Sam's parent has orange eyes and white skin. On the other hand, Carole, another MendAlien, possesses orange eyes and white skin. If Sam and Carole were to mate, what would be the predicted phenotypic ratio of their offspring?
Question:
What is the predicted phenotypic ratio of Sam and Carole's offspring?
A. 1 black eyes, green skin : 3 black eyes, white skin : 3 orange eyes, green skin : 9 orange eyes, white skin.
B. There is insufficient information to determine Sam's genotype.
C. 3 black eyes, green skin : 3 black eyes, white skin : 9 orange eyes, green skin : 1 orange eyes, white skin.
D. 1 black eyes, green skin : 1 black eyes, white skin : 1 orange eyes, green skin : 1 orange eyes, white skin.
E. 9 black eyes, green skin : 3 black eyes, white skin : 3 orange eyes, green skin : 1 orange eyes, white skin.
Answer:
Answer: D. 1 black eyes, green skin : 1 black eyes, white skin : 1 orange eyes, green skin : 1 orange eyes, white skin
Explanation:
We have two genes with the following alleles:
- Gene 1 (Eye Color):
- BB or Bb: black eyes
- bb: orange eyes - Gene 2 (Skin Color):
- GG or Gg: green skin
- gg: white skin
Sam's parent had orange eyes and white skin, indicating the genotype bbgg. Sam inherited the alleles b and g, resulting in a genotype of BbGg. This means Sam is heterozygous for both genes.
Carole has orange eyes and white skin, leading to a genotype of bbgg. Carole will only produce bg gametes.
By performing a Punnett Square using Sam's genotype (BbGg) and Carole's genotype (bbgg), we can determine the possible combinations of alleles for eye and skin color in their offspring:
- 1/4 BbGg: black eyes, green skin
- 1/4 Bbgg: black eyes, white skin
- 1/4 bbGg: orange eyes, green skin
- 1/4 bbgg: orange eyes, white skin
Therefore, the predicted phenotypic ratio of Sam and Carole's offspring would be 1 black eyes, green skin : 1 black eyes, white skin : 1 orange eyes, green skin : 1 orange eyes, white skin.