pedigree is for an X-linked trait.

Complete the following and submit the Word document by midnight Sunday. Remember to include complete citations for all sources used to answer each question.

1. Marfan syndrome follows a pattern of autosomal dominant inheritance. What is the chance (= probability) that any child will inherit the dominant allele if one parent (Parent #1) does not carry the allele and the other (Parent #2) is heterozygous for it? Provide a clear explanation and complete the Punnett Square below. Be sure to define the letters you use for the two alleles:

2. Below is a diagram showing the inheritance of an X-linked trait; the first generation is at the top and the third generation is at the bottom. Describe what this pedigree depicts in terms of gender, presence or absence of the disorder, and what feature(s) indicate that the pedigree is for an X-linked trait.

3. In one experiment, Mendel crossed a pea plant that bred true for green pods with one that bred true for yellow pods. All of the F1 plants had green pods. What does it mean when an organism like Mendel’s pea plants is true breeding? Which form of the trait (green or yellow pods) is dominant? Explain how you arrived at your conclusion. This should include the possible genotypes of the parents involved in the cross and those of the F1 generation.

4. What type of mutation has occurred in the DNA of people with sickle cell anemia?  (Look back, if you need to, to see what causes sickle cell.)

5. A man who has type B blood and a woman who has type A blood could have children of which phenotypes? Explain your answer; be sure to consider what the possible genotypes are for both parents in your answer.

6. Unattached earlobes are a dominant trait.  If A denotes the allele for unattached earlobes, and a denotes the allele for attached earlobes, what is (are) the possible genotype(s) of a person who has unattached earlobes?

Could both parents of a person with unattached earlobes have attached earlobes? Why or why not? Think about what the parent’s genotypes have to be.

7. How are a locus, allele and a gene similar? How would you differentiate among these three terms?

8. Explain what is meant by polygenic inheritance, pleiotropy, and human gene therapy. Provide an example of each.