Questions and Answer to Problem Sets
CHAPTER 1
Application and Experimental Questions
E1.Pick any example of a genetic technology and describe how it has directly impacted your life.
Answer: There are many possible answers. Some common areas to discuss might involve the impact of genetics in the production of new medicines, the diagnosis of diseases, the production of new kinds of food, and the use of DNA fingerprinting to solve crimes.
E2.What is a genetic cross?
Answer: A genetic cross involves breeding two different individuals.
E3.The technique known as DNA sequencing (described in Chapter 20) enables researchers to determine the DNA sequence of genes. Would this technique be used primarily by transmission geneticists, molecular geneticists, or population geneticists?
Answer: This would be used to a great extent by molecular geneticists. The sequence of DNA is a molecular characteristic of DNA. In addition, as we will learn throughout this textbook, the sequence of DNA is interesting to transmission and population geneticists as well.
E4.Figure 1.5 shows a micrograph of chromosomes from a normal human cell. If you performed this type of experiment using cells from a person with Down syndrome, what would you expect to see?
Answer: You would see 47 chromosomes instead of 46. There would be three copies of chromosome 21 instead of two copies.
E5.Many organisms are studied by geneticists. Of the following species, do you think it would be more likely for them to be studied by a transmission geneticist, a molecular geneticist, or a population geneticist? Explain your answer. Note: More than one answer may be possible.
A.Dogs
B.E. coli
C.Fruit flies
D.Leopards
E.Corn
Answer:
A. Transmission geneticists. Dog breeders are interested in how genetic crosses affect the traits of dogs.
B.Molecular geneticists. This is a good model organism to study genetics at the molecular level.
C.Both transmission geneticists and molecular geneticists. Fruit flies are easy to cross and study the transmission of genes and traits from parents to offspring. Molecular geneticists have also studied many genes in fruit flies to see how they function at the molecular level.
D.Population geneticists. Most wild animals and plants would be the subject of population geneticists. In the wild, you cannot make controlled crosses. But you can study genetic variation within populations and try to understand its relationship to the environment.
E.Transmission geneticists. Agricultural breeders are interested in how genetic crosses affect the outcome of traits.
E6.Pick any trait you like in any species of wild plant or animal. The trait must somehow vary among different members of the species. For example, some butterflies have dark wings and others have light wings (see Figure 1.7).
A.Discuss all of the background information that you already have (from personal observations) regarding this trait.
B.Propose a hypothesis that would explain the genetic variation within the species. For example, in the case of the moths, your hypothesis might be that the dark moths survive better in places where the trees are dark, while the light moths survive better in places where the trees are covered with lightly colored lichens.
C.Describe the experimental steps you would follow to test your hypothesis.
D.Describe the possible data you might collect.
E.Interpret your data.
Note: When picking a trait to answer this question, do not pick the trait of wing color in moths.
Answer: You need to follow the scientific method. You can take a look at an experiment in another chapter to see how the scientific method is followed.