Evolutionary Medicine (TEST 3)

Question 1

Evolutionary Medicine

Answer 1

Application of evolutionary history to study present day diseases

Question 2

what is more important: the why or the how- in evolutionary medicine?

Answer 2

the WHY not the HOW they get sick

Question 3

What are the two uses of evolutionary medicine?

Answer 3

• To understand disease processs

- To create effective treatment

Question 4

What are three other modern applications of evolution?

Answer 4

1) Ag
2) Biotech
3) computer science

Question 5

What is the MAIN purpose of evolutionary medicine?

Answer 5

to understand causes and persistence of disease

Question 6

Enviroment of Evolutionary Adaptedness

Answer 6

if environments change rapidly, organisms may not be adapted to altered conditions; adaptations useful in previous conditions cause medical problems under altered condition

Question 7

Senescense

Answer 7

decline in fertility & survival late in life

Question 8

What are the three main hypothesis for the evolution of aging;

Answer 8

1) Irrepairable damage
2) Mutation Accumulation
3) Antagonistic Pleiotropy:

Question 9

Irrepairable Damage

Answer 9

as we age, disposable soma deteriorates

Question 10

Support for Irrepairable damage hyp?

Answer 10

males senesce earlier than females in species under

intense intra-sexual selection

Question 11

Argument against Irrepairable damage hyp?

Answer 11

metabolic rates do not correlate with lifespan in mammals e.g., bats (high metabolic rates) do not live shorter lives - assumes that selection cannot improve mechanisms to repair damage (e.g., assumes there is no genetic variation for repair efficiency) and predicts that lifespan cannot be
selected on, contrary to results of selection experiment

Question 12

Mutation Accumulation

Answer 12

Less selection later in life so deleterious mutations become more prevelent

Question 13

Is their heritable variation in aging?

Answer 13

The observation that there exists heritable variation in longevity (i.e., selection can lengthen lifespan) weakens the Irreparable Damage Hypothesis for senescence

Question 14

Intensity of selection on late-acting genes declines because of what two reasons?

Answer 14

(a) they affect fewer individuals in a population

(b) they are already passed on before they act

Question 15

Antagonistic Pleiotropy

Answer 15

mutations with strong positive effects early in life AND negative effects late in life can be selected for (trait has a positive and a negative phenotypic effect, and the two effects occur at different times)

Question 16

Pleiotropy

Answer 16

multiple phenotypic effects caused by single gene

Question 17

Which Hypothesis have the most support?

Answer 17

1 and 2

Question 18

Virulence

Answer 18

Measure of fitness impact of pathogen/parasite on host (** function of the interaction between host and
pathogen/parasite)

Question 19

Myxomatosis

Answer 19

viral disease of rabbits cause by myxoma virus acute conjunctivitis and blindness secondary bacterial infections (e.g., pneumonia) death within about 5-15 days

Question 20

Why did they introduce the myxoma to australian rabbits?

Answer 20

For species control (there were too many)

Question 21

What could we predict would happen evolutionarily in the rabbit case?

Answer 21

1. evolution of resistance in rabbits

2. evolution of reduced fitness-impact of virus

Question 22

Which happened in the rabbits and why?

Answer 22

Reduced fitness-impact of virus because the Myxoma virus is transmitted via a vector (mosquito) and tradeoff occured

Question 23

Tradeoff

Answer 23

host survival vs. colonization rate (if it takes a long time to colonize the virus more hosts start surviving)

Question 24

What is the effect in a low virulence virus?

Answer 24

Low infectivity - High host survival (= high host longevity when sick)

Question 25

High Virulence Viruses

Answer 25

• High infectivity - Low host survival (= low host longevity when sick)

Question 26

Vertical transmission

Answer 26

parasite/pathogen fitness is determined by the survival/reproduction of the current host.
•Reproductive interests of parasite and host are aligned
•=> low fitness-impact tends to evolve

Question 27

Lateral Transmission

Answer 27

parasite/pathogen fitness is determined not only by the survival/reproduction of the current host, but also by the number of new hosts colonized.
•Reproductive interests of parasite and host are NOT aligned.
•=> high fitness-impact tends to evolve

Question 28

What are the three ways virulence evolves?

Answer 28

1) Tradeoff
2) Lateral Vs. Vertical Transmission
3) Number of pathogen strains

Question 29

What is the deal if you have a single infection in host?

Answer 29

There are no competitions between strains so virulence is maintaned

Question 30

What is the deal if you have multiple infections?

Answer 30

Competition between the strains results in a selection for high virulence

Question 31

Describe the malaria study about number of infections?

Answer 31

Mice infected with multiple strains of malaria evolve higher fitness impact (higher virulence)