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Flashcards in Evolutionary Medicine (TEST 3) Deck (31):
1

Evolutionary Medicine

Application of evolutionary history to study present day diseases

2

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

the WHY not the HOW they get sick

3

What are the two uses of evolutionary medicine?

-To understand disease processs
-To create effective treatment

4

What are three other modern applications of evolution?

1)Ag
2)Biotech
3) computer science

5

What is the MAIN purpose of evolutionary medicine?

to understand causes and persistence of disease

6

Enviroment of Evolutionary Adaptedness

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

7

Senescense

decline in fertility & survival late in life

8

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

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

9

Irrepairable Damage

as we age, disposable soma deteriorates

10

Support for Irrepairable damage hyp?

males senesce earlier than females in species under
intense intra-sexual selection

11

Argument against Irrepairable damage hyp?

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

12

Mutation Accumulation

Less selection later in life so deleterious mutations become more prevelent

13

Is their heritable variation in aging?

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

14

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

(a) they affect fewer individuals in a population
(b) they are already passed on before they act

15

Antagonistic Pleiotropy

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)

16

Pleiotropy

multiple phenotypic effects caused by single gene

17

Which Hypothesis have the most support?

1 and 2

18

Virulence

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

19

Myxomatosis

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

20

Why did they introduce the myxoma to australian rabbits?

For species control (there were too many)

21

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

1. evolution of resistance in rabbits
2. evolution of reduced fitness-impact of virus

22

Which happened in the rabbits and why?

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

23

Tradeoff

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

24

What is the effect in a low virulence virus?

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

25

High Virulence Viruses

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

26

Vertical transmission

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

27

Lateral Transmission

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

28

What are the three ways virulence evolves?

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

29

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

There are no competitions between strains so virulence is maintaned

30

What is the deal if you have multiple infections?

Competition between the strains results in a selection for high virulence

31

Describe the malaria study about number of infections?

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