Genetics (L15)

Question 1

3 Influences over evolutionary pathways

Answer 1

1. heritable genetic variation
2. changes in allele freq (via. ev forces)
3. environment

Question 2

4 evolutionary forces

Answer 2

o Mutation:
o Random genetic drift:
o Gene flow
o Natural selection

Question 3

principals of mutation

Answer 3

• makes variation,
• changes at a relativly slow rate
• Weak ev force

Question 4

principals of RGD

Answer 4

• deletes variation (within pop)
• increases diversity b/w pops
• greater change in smaller pop

Question 5

Principals of gene flow

Answer 5

mixes variation, 
counteracts drift (inc pop + inc similarity- homogenising)

Question 6

principals of NS

Answer 6

selects variation, is directional

Question 7

in RGD what happens when smaller pop

Answer 7

, smaller pop is quicker fixed/lost

Question 8

what is RGD inversely proportional to

Answer 8

population (1/2Ne)

Question 9

why did RGD influence early humans

Answer 9

small pops

Question 10

principals of founder effect

Answer 10

• type of RGD

reduce genetic diversity within population and increase diversity between populations

Question 11

DIFF b/w migration + gene flow

Answer 11

• Migration = movement, gene flow= movement + mating

Question 12

explain sex specific differences in RGD

Answer 12

patriocality= women move to men
= moving group less diverse (b/w pop) but more diverse w/in
= holding group more difference b/w + more sim within

Question 13

evidence that shows patrilocal movement

Answer 13

mitochondrial similar (bc women are moving)

Question 14

what are the 2 measures of fitness (reproductive success)

Answer 14

• Viability (survival, mortality)

* Fertility

Question 15

what is the only adaptive force

Answer 15

NS

Question 16

What does ROChange of NS depend on

Answer 16

1. mode of expression (dom/rec)

2. selection strength + initial allele frequ

Question 17

how does ROC with mode of expression

Answer 17

Dom= multiple genotype express phenotype // speed increase is greater

Question 18

how does ROC with strength of selection + initial allele freq

Answer 18

• High intial freq= more likely to be fixed

* Stronger selection= quicker selection

Question 19

what is balancing selection

Answer 19

heterozygote advantage

- • Maintaining selection even if deleterious

Question 20

what does the CCR5 gene do

Answer 20

• In human genome= mutation

* Variation where no HIV receptor

Question 21

why isn’t CCR5 gene prevalent in countries its needed

Answer 21

• initial freq too low

Question 22

how can CCR5 be maladaptive

Answer 22

CCR5 deficiency= increase risk of west nile virus

Question 23

why is expected replacement rate (aa change) not followed for variation

Answer 23

Rate for silent change is actually higher (deleterious effect of replacement taken into account as a selective pressure)