Young: Medical Genetics - Extended Matching Questions

Table of Contents

1. Chapter 7
   1. Question 1
   2. Question 2

Question 1

Instructions: Each group of extended matching questions consists of lettered options followed by a list of numbered problems/questions. For each numbered problem/question select the one lettered option that is most closely answers the question. You can use the lettered options once, more than once, or not at all.

Theme: Population genetics

Options:

1. Migration and gene flow
2. Heterozygote advantage
3. Founder effect and genetic drift
4. Assortative mating
5. Consanguinity
6. Unequal mutation-selection equilibrium

Select the most appropriate explanation for the following observations from the available options.

1

Scenario 1   The high incidence of sickle-cell disease in Afro-Caribbeans. Choose... Migration and gene flow Heterozygote advantage Founder effect and genetic drift Assortative mating Consanguinity Unequal mutation-selection equilibrium It has been clearly shown that carriers of the sickle-cell trait show increased resistance to infection with falciparum malaria when compared with non-carriers. See Page 139 and 157.Incorrect. See Page 139.Your answer has been saved.

2

Scenario 2   The high incidence of variegate porphyria in white South Africans. Choose... Migration and gene flow Heterozygote advantage Founder effect and genetic drift Assortative mating Consanguinity Unequal mutation-selection equilibrium There is a common variegate porphyria mutation in the South African white population which can be traced back to a single pair of emigrants from the Netherlands. See Page 140 and 218.Incorrect. See Page 218.Your answer has been saved.

3

Scenario 3   The high incidence of haemochromatosis in Western Europeans. Choose... Migration and gene flow Heterozygote advantage Founder effect and genetic drift Assortative mating Consanguinity Unequal mutation-selection equilibrium Several explanations are possible but the main factor is probably gene flow stemming from the Viking conquests of western Europe in the middle ages. See Page 140.Incorrect. See Page 140.Your answer has been saved.

4

Scenario 4   The high incidence of cartilage-hair hypoplasia in Finland. Choose... Migration and gene flow Heterozygote advantage Founder effect and genetic drift Assortative mating Consanguinity Unequal mutation-selection equilibrium Finland has been relatively isolated geographically and this is probably the reason why several otherwise rare disorders such as cartilage-hair hypoplasia show a high frequency in this population. See Page 140.Incorrect. See Page 140.Your answer has been saved.

5

Scenario 5   The high incidence of cystic fibrosis in Western Europeans. Choose... Migration and gene flow Heterozygote advantage Founder effect and genetic drift Assortative mating Consanguinity Unequal mutation-selection equilibrium The fact that a single mutation (ΔF508) is so common (Page 108) suggests that heterozygote advantage is the likely explanation for the high frequency of cystic fibrosis. Studies in mice indicate that carriers may have increased resistance to typhoid. Page 140.Incorrect. See Page 140.Your answer has been saved.