Pay special attention to the differences between monogenic (or Mendellian) traits and polygenic traits. Also, be careful with the terms “dominant” and “recessive”. The dominant form of a trait isn’t stronger, better, or more common than the recessive. The dominant form of a trait is simply the one that shows in the heterozygous state, while the recessive form only shows in the homozygous.
Answer ANY three questions.
- How does the manifestation of polygenic traits differ from Mendellian traits? Why? What is an example of a polygenic trait? How does the pleiotrophic effect differ from the effects of polygenic traits?
- The inheritance of some traits, such as hemophilia, do not follow the classic Mendelian rules. Why?
- What is linkageand why did Mendel not observe it? Do you think he would have been able to formulate his postulates had the traits he used been linked?
- Mendel is often said to have been “ahead of his time.” Why? Do you think such a delay between the discovery and the recognition of what that discovery might mean could happen today? Why or why not?
- Explain the difference between structural and regulatory genes. What is the role of regulatory genes in creating variation between related species?
- Explain the mechanics of the ABO blood system. What is the relationship between genotype and phenotype within this system? Be sure to include the terms recessive, dominant, andcodominant.
- Using obesity as an example, explain the complex relationship between genes, environments and phenotypes.
- Outline and explain Mendel’s postulates.
- Using specific examples, explain the difference between autosomal recessive disordersand autosomal dominant disorders.
- Citing examples, explain how some mutations can be bad while others may be neutral.
- Discuss the concept of heritability. How might twin studies help us determine heritability?
- What is PKU and how is it inherited? Explain how PKU is as much a result of environment as it is of genetics.
- Watch the video- War on the Weak; Eugenics in AmericaIn the past, there have been groups who have promoted the concept of eugenics. What is eugenics? What are the ethical concerns about such programs?
- What is the role of genetic knowledge in our day-to-day lives? Should genetic information about us be made available to employers or health insurance providers? Would you want to know if you have an allele that might cause you to have a fatal illness 20 years from now?
- Folk singer Woody Guthrie died of the complications of Huntington’s Chorea (Huntington’s is inherited as an autosomal dominant). The disease is incurable, largely untreatable and leads to early death. Symptoms usually occur when the individual is in their 40’s. Woody’s son Arlo declined to be tested when the test for the gene became available. At the time, Arlo had teenage children, and did not plan on having any more. What would the test have told Arlo? Why do you think he did not want to take the test? Do you agree with his decision? Why or why not? Assuming that Arlo did inherit the disease from his father, what are the chances that he would have passed it on to his own children?
- What are the functions of a genetic counselor? Who should seek genetic counseling? Can you think of any reasons why someone would not want to know if they carry a genetic disease?