Mutations

Question 1

CCR5 delta 32

Answer 1

• CC Chemokine receptor 5
• 32 base pair deletion
• non-functioning protein
• protein receptor doesn’t make it to surface
• no receptor = HIV-1 cannot enter in homozygotes
• HIV can’t infect cells, no T cell death
• homozygotes immune to HIV
• higher prevalence in N. European descent

Question 2

Cystic Fibrosis

Answer 2

• membrane bound protein (chloride channel)
• over 2500 mutations, F508del most common
• mutated protein sometimes reaches surface, sometimes degraded (dependent on mutation)
• reduced functionality/no chloride channel at cell membrane
• other channels don’t work properly
• build up of mucus in lungs
• salty sweat
• lac of pancreatic enzymes
• coughing, poor growth, lung infection, early death
• 1/20 carriers (European descent)

Question 3

Lactase permanence

Answer 3

• point mutation in European descent (-13910*T)
• continued production of lactase past weening
• able too digest milk, obtain nutrients and energy
• different mutations in Africa, Middle East, Europe
• lactose persistence = gene-culture co-evolution AND convergent evolution

Question 4

Sickle Cell Anemia

Answer 4

• point mutation in Beta Globin Gene
• substitution of Valine to Glutamic Acid
• fibre formation
• mutated protein moves through protein production pathway
• hemoglobin takes on sickle shape
• cleared 10-20 days, normal = 120 days
• block small blood vessels, prevent movement of O2 carrying blood
• Anemia, pain crisis, jaundice, stroke
• 1/12 (African descent)
• Heterozygotes = advantage against malaria