Human Genetics
Exercise 1: genotype to Phenotype
A. Why was the male chosen to determine the sex of the child?
B. Draw a picture of the compiled traits.
C. If this activity was repeated two or three times would the offspring images change? Explain your answer.
Exercise 2: Punnett Squares
A. Dominant: cheek freckles
A man with a heterozygous gene for freckles on his cheeks has a child with a woman who does not have freckles on her cheeks. What is the likelihood that their son will have freckles on his cheeks?
B. Dominant: normal; no cystic fibrosis
A woman has a history of cystic fibrosis in her family, and found out that she has the gene for cystic fibrosis, but is not affected by the gene. Her husband also has a history of cystic fibrosis in his family. He got tested yesterday and found that he is also a carrier for the disease, but is not affected by it. They are going to have a baby in two months. What is the likelihood that their baby will have cystic fibrosis?
C. Dominant: normal; no Tay-Sachs
A man is a carrier for Tay-Sachs. He is going to have a child with a woman who has homozygous normal genes. What are the chances that they will have a child who has Tay-Sachs disease?
D. Dominant:
A woman with heterozygous genes for a round face shape and a chin that is not prominent has a child with a man who has a square face and homozygous genes for a prominent chin. What are the chances that the child has a square face with a prominent chin?
E. Dominant: Huntington's disease
A man with Huntington's disease is also a carrier for cystic fibrosis. His wife has cystic fibrosis but does not have Huntington's disease. If they have a baby, what is the likelihood that the baby will have both Huntington's disease and cystic fibrosis?
F. X-linked dominant trait:
A color-blind man marries a non-color-blind woman who is not a carrier for color blindness. What are the chances that they will have a son who is also color-blind?
What are the chances that they will have a daughter who is a carrier for color blindness?