Explain why analyzing mitochondrial DNA or Y chromosome DNA cannot provide a complete picture of an individual’s ancestry.
Please answer each question fully and in complete sentences. You may use your textbook, class notes, and/or PowerPoint slides, and resources indicated in the questions below; if you use other resources, they must be cited properly in a working bibliography (author, article title, journal or book title, date of publication, page numbers) at the end of the exam. Please do not discuss these questions with your classmates: this should be your own work. Each question is worth 10 points.
Should a woman be held legally responsible if she drinks alcohol, smokes, or abuses drugs during pregnancy and it harms her child (e.g., fetal alcohol syndrome)? If so, should liability apply to all substances that can harm a fetus, or only to those that are illegal? For example, we know that maternal weight gain in pregnancy is associated with an increased risk for diabetes in their children. What evidence or reasoning leads you to this opinion? (N.B.: there is no right or wrong answer here—I am looking to see if you state your opinion and then give sound reasoning for it.)
Many genes contribute to lung cancer risk, especially among people who smoke tobacco. These genes include p53, IL1A, IL1B, CYP1A1, EPHX1, TERT, and CRR9. Search for one of these genes online and describe how mutations in the gene may contribute to causing lung cancer, or how polymorphisms in the gene may be associated with increased risk in combination with smoking. Be sure to choose a trustworthy source and cite the source with your answer.
Malnutrition is common among children in the African nation of Malawi. Researchers hypothesized that the microbiome may play a role in starvation because in some families, some children are malnourished and their siblings are not, even though they eat the same diet. Even identical twins may differ in nutritional status.
Researchers followed 317 sets of twins in Malawi, from birth until age 3. In half of the twin pairs, one or both twins developed kwashiorkor, the type of protein malnutrition that swells bellies. The researchers focused on twin pairs in which only one was starving, including both identical and fraternal pairs. At the first sign that one twin was malnourished, both were placed on a diet of healthy “therapeutic food.” Four weeks later, the pair returned to the nutrient-poor village diet. If the malnourished twin became so again, then the researchers compared his or her microbiome to that of the healthy sibling. The goal was to identify bacterial species that impair the ability of a child to extract nutrients from the native diet. [Smith, et al. (2013) Gut microbiomes of Malawian twin pairs discordant for kwashiorkor. Science 339(6119):548-554.]
How might the findings from this study be applied to help prevent or treat malnutrition? Do you think that the study was conducted ethically? Why or why not? Explain how identical twins who follow the same diet can differ in nutritional status.
The environmental epigenetics hypothesis states that early negative experiences, such as neglect, abuse, and extreme stress, increase the risk of developing depression, anxiety disorder, addictions, and/or obesity later in life through effects on gene expression that persist and can be passed on to the next generation. Suggest an experiment to test this hypothesis.
Population bottlenecks are evident today in Arab communities, Israel, India, Thailand, Scandinavia, some African nations, and especially among indigenous peoples such as Native Americans. Research an indigenous or isolated population and describe a genetic condition that its members have that is rare among other groups of people, and how the population bottleneck occurred.
Explain why analyzing mitochondrial DNA or Y chromosome DNA cannot provide a complete picture of an individual’s ancestry. How can a female trace her paternal lineage if she does not have a Y chromosome?
Go to clinicaltrials.gov and search under “gene therapy.” Describe one of the current research trials for correcting a genetic problem. Include information about the genetic condition if available, including: mode of inheritance, age of onset, symptom severity, variability in expression, existing treatments (standard of care), and how the gene therapy is proposed to correct the problem.