Evolutionary Medicine

Question 1

What is antigenic drift?

Answer 1

changes in a virus due to mutations that affects surface hemagglutinin/neuraminidase, allowing the virus to bypass antibodies (no recognition)

Question 2

What is antigenic shift?

Answer 2

changes in a virus due to viral reassortment (combining viral strains) to create new subvariants of hemagglutinin/neuraminidase which creates a new strain

Question 3

Through what process can an avian flu spread to mammals?

Answer 3

viral reassortment

Question 4

How did the 2002 SARS pandemic start?

Answer 4

• strains of a virus found in bats began reassorting in a cave in China
• reassortment created a strain that could infect civets (mammal)
• civets passed the virus into humans via meat trade

Question 5

What are zoonotic strains and how are they related to the MERS pandemic?

Answer 5

• zoonotic strains = strains that can jump between hosts of different species
• MERS started in bats, then camels and finally humans in the Middle East

Question 6

What factors allow pathogens to rapidly evolve?

Answer 6

• high mutation rate
• high reproductive rate
• horizontal transmission + reassortment of genetic material

Question 7

Why did smallpox affect the Indigenous peoples of North America so severely?

Answer 7

they did not have the long co-evolutionary history with the virus like the Europeans had (no immunity)

Question 8

What is an example of a genetic bottleneck increasing the frequency of a disease?

Answer 8

Ellis-van-Creveld syndrome in Pennsylvania (genetic drift + inbreeding)

Question 9

What is an example of an evolutionary trade-off seen in aging?

Answer 9

when young: genes that reflect maintenance (survival, growth and reproduction) are favoured

when older: these same genes can reduce overall health (antagonistic pleiotropy)

Question 10

What is the P53 gene?

Answer 10

• suppresses tumor growth
• can damage healthy cells and cause tumors later in life if the gene becomes mutated

Question 11

What are proto-oncogenes and oncogenes?

Answer 11

proto-oncogene = genes that maintain normal cell division

oncogene = mutated proto-oncogene that can cause abormal cell division (tumors)

Question 12

Who/where are you most likely to find cancerous growth?

Answer 12

• in children (high rates of cell division because of growing stages)
• continuously replaced tissue (skin, colon etc.)
• older people (due to accumulations of cancerous mutations)