Case study:
1. Lana S. seemed to be a healthy newborn. In fact, she seemed to be hitting developmental milestones ahead of schedule, trying to lift her head up at only 3 weeks. But then she rapidly lost skills. Her head flopped, she stopped trying to turn over, and her arms and legs became spastic. When she no longer made eye contact, her anxious parents took her to the pediatrician. She referred the family to a pediatric neurologist, who was puzzled. "She has all the symptoms of Canavan disease, but that can't be. You're not Jewish." Explain how the neurologist was incorrect.
2. The human population of India is divided into many castes, and the people follow strict rules governing who can marry whom. Researchers compared several genes among 265 Indians of different castes and 750 people from Africa, Europe, and Asia. The study found that the genes of higher Indian castes most closely resembled those of Europeans, and that the genes of the lowest castes most closely resembled those of Asians. In addition, maternally inherited genes (mitochondrial DNA) more closely resembled Asian versions of those genes, but paternally inherited genes (on the Y chromosome) more closely resembled European DNA sequences. Construct an historical scenario to account for these observations.
3. A magazine article featured parents who filed a "wrongful birth" lawsuit against their doctor for failing to offer prenatal testing for spina bifida, which their daughter was born with in 2003-even though they love the child dearly. They will not say whether they would have ended the pregnancy had they known about the birth defect. If they had ended it, would that have been a eugenic act? Explain your answer.
Assignment Grading Criteria Submitted the document for the case study in "Changing Allele Frequencies" and it contained the following:
Explained why the increased prevalence of sickle-cell disease among African Americans has more to do with the environmental factors than the skin color or other phenotypes used to define races. Described other examples of balanced polymorphism.
Identified a population group (other than African Americans) with a high prevalence of sickle-cell disease. Listed six genetic diseases more common among Ashkenazi Jews than among other population groups.