#41. Use the following information to answer the next question.
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: GgBbcross x GgBB GGBbcross xGGBb
Percentage of
Offspring:
#42. Below is a simplified chart for polygenic trait of eye colour. The amount of melanin in the iris is what determines the colour of the eye. People with brown eyes have more melanin in their iris than people with blue eyes. The amount of melanin is controlled by how many dominant alleles a person has for eye colour as follows:
Number of Dominant Alleles Genotypes Phenotypes
4 AABB Very dark brown eyes
3 AaBB or AABb Brown eyes
2 AaBb, aaBB etc. Light brown or hazel eyes
1 Aabb or aaBb Dark blue eyes
0 aabb Light blue eyes
Which of the following parental crosses explains how two brown-eyed parents can produce a blue-eyed child?
Select one:
a. Aabb cross times AABB
b. AaBB cross times AaBb
c. AABB cross times AaBb
d. AaBB cross times AABb
Thank you so much for your help bio_man. Have a good afternoon
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