L16 - population genetics

Question 1

what factors affect allele frequency

Answer 1

1. natural selection
2. gene mutation
3. migration
4. genetic drift (due to chance)
5. founder effects + genetic bottlenecks

Question 2

define population

Answer 2

individuals of same species in certain geographical area (that can interbreed)

Question 3

why do we use hardy Weinberg equation

Answer 3

to work out allele frequency of a population

Question 4

by what principle does the hardy weinberg equation work

Answer 4

with random mating and no evolutionary change, allele frequency are in stable equilibrium

Question 5

what are the assumptions of the hardy weinberg equation (7)

Answer 5

the freq of alleles in gene pool doesn’t change over time:

1. pop size infinitely large
2. random mating
3. no natural selection
4. no migration into pop (no new alleles)
5. no mutation (no new alleles)
6. no genetic drift
7. diploid organism

Question 6

describe natural selection

Answer 6

• individuals of species exhibit genetic variation
• organisms reproduce exponentially (more than can survive)
• some phenotypes (and their alleles) are better suited to the environment and will therefore survive
• phenotypes more suited for survival become more common

Question 7

what can cause genetic drift

Answer 7

founder effect
genetic bottleneck
(due to chance)

Question 8

explain founder effect

Answer 8

when a population is suddenly reduced /isolated (eg migration) the allele variation will decrease

Question 9

explain genetic bottleneck

Answer 9

(type of founder effect)

when a population drastically reduced due to natural disaster the variation in alleles decreases

Question 10

explain founder effect on alleles

Answer 10

new smaller pop will reproduce causing a difference in allele frequencies due to less variation in gene pool (no longer equilibrium)

Question 11

define inbreeding

Answer 11

mating between related individuals

Question 12

when is genetic drift particularly visible?

Answer 12

small populations

Question 13

explain how inbreeding affects alleles and genotypes

Answer 13

• individuals will share bigger proportion of alleles
• leads to increased freq of homozygous genotypes (less variation)
• individuals more likely to suffer inherited disease

Question 14

what is molecular evolution

Answer 14

sequencing DNA of individuals to see its change over time

Question 15

how can founder effect affect disease?

Answer 15

higher frequency of autosomal recessive disorders

Question 16

what type of DNA makes best use as evolutionary clock?

Answer 16

non coding regions

because changes in coding regions can be detrimental to organism