What are some characteristics of model genetic organisms that make them useful for genetic studies?

Why do you think all organisms use nucleic acids for encoding genetic information? Why not use proteins or carbohydrates? What advantages might DNA have as the source of genetic information?

Suppose that you could undergo genetic testing at age 18 for susceptibility to a genetic disease that would not appear until middle age and has no available treatment. a. What would be some of the possible reasons for having such a genetic test and some of the possible reasons for not having a test? b. Would you personally want to be tested? Explain your reasoning.

A 45-year-old woman undergoes genetic testing and discovers that she is at high risk for developing colon cancer and Alzheimer's disease. Because her children have 50% of her genes, they may also be at an increased risk for these diseases. Does she have a moral or legal obligation to tell her children and other close relatives about the results of her genetic testing?

Do you support or oppose the development of genetically engineered foods (genetically modified organisms, or GMOs)? Find someone who takes the opposite position and discuss this question with them. Think about the economic and environmental benefits, health risks, ecological effects, and social impact of their use. List some reasons for and against genetically engineering the foods we eat.

Give at least three examples of the role of genetics in society today.

Choose one of the ethical or social issues in parts a through e and give your opinion on the issue. For background information, you might read one of the articles on ethics marked with an asterisk in the Suggested Readings section for $\text{\blue{Chapter 1}}$ in your Sapling Plus.
a. Should a person’s genetic makeup be used in determining his or her eligibility for life insurance?
b. Should biotechnology companies be able to patent newly sequenced genes?
c. Should gene therapy be used in people?
d. Should genetic testing be made available for inherited disorders for which there is no treatment or cure?

Suppose that life exists elsewhere in the universe. All life must contain some type of genetic information, but alien genomes might not consist of nucleic acids and have the same features as those found in the genomes of life on Earth. What might be the common features of all genomes, no matter where they exist?

We now know a great deal about the genetics of humans, and humans are the focus of many genetic studies. What are some of the reasons humans have been the focus of intensive genetic study?

The type of albinism that arises with high frequency among Hopi Native Americans (discussed in the introduction to this chapter) is most likely oculocutaneous albinism type 2, due to a defect in the OCA2 gene on chromosome 15. Do some research on the Internet to determine how the phenotype of this type of albinism differs from the phenotypes of other forms of albinism in humans and to identify the mutated genes that result in those phenotypes. Hint: Visit the Online Mendelian Inheritance in Man Website $\text{\blue{(http://www.ncbi.nlm.nih.gov/omim/)}}$ and search the database for albinism.

Compare and contrast the following terms:
a. Eukaryotic and prokaryotic cells
b. Gene and allele
c. Genotype and phenotype
d. DNA and RNA
e. DNA and chromosome

Briefly explain why each of the following theories is incorrect:
a. Pangenesis
b. Preformationism
c. Blending inheritance
d. Inheritance of acquired characteristics

Match each of the descriptions (a through d) with the correct theory or concept listed below. Preformationism Pangenesis Germ-plasm theory Inheritance of acquired characteristics
a. Each reproductive cell contains a complete set of genetic information.
b. All traits are inherited from one parent.
c. Genetic information may be altered by the use of a characteristic.
d. Cells of different tissues contain different genetic information.

Genetics is said to be both a very old science and a very young science. Explain what is meant by this statement.