Population Genetics

Question 1

polymorphism

Answer 1

allele present in more than 1% of the pop

diff of one nucleotide = single nucleotide polymorphism (SNP), not usually cause disease

Question 2

high polymorphic genes

Answer 2

HLA genes = immune response, variable so people not all die at same time

predicts that diversity of function is importnat

Question 3

non-polymorphic genes

Answer 3

histone gene sequences, highly conserved aka gene function optimized so any change reduces fitness

Question 4

hardy weinberg principle

Answer 4

model for distribution of alleles in pops aka predicts allele frequencies in a pop will not change over time

Question 5

hardy weinberg assumptions

Answer 5

1. pop is large
2. no new mutations
3. all genotypes have same fitness (no selection)
4. mating is random
5. no influx or efflux of alleles (migration of people)

Question 6

factors disturbing equilibrium

Answer 6

1. genetic drift for small populations
2. new mutations
3. selection (unequal fitness)
4. assortative mating (nonrandom)
5. bottlenecks and founder effect for pops

Question 7

hardy weinberg equations

describe

Answer 7

allele freq in a gene pool of a pop
genotype freq in a pop

must know mutant allele freq
only work in ideal pops

Question 8

hardy weinberg equations

Answer 8

p + q = 1
binomial formula: p2 + q2 + 2(pq) = 1
possible genotypes: pp(normal) or pq (hetero) or qq

Question 9

homozygous

Answer 9

q2

Question 10

heterozygous

Answer 10

2pq

Question 11

homozygote deviations

Answer 11

assortative mating (not limited to consanguinity) inc homo

low fitness dec homo freq

Question 12

genetic drift

Answer 12

can eliminate mutant allele

Question 13

selection

Question 14

assortative mating

Answer 14

still same freq of mutant alleles but heterozygous dec and homo inc freq (aka redistribution)

Question 15

bottlenecks

Answer 15

reshape entire gene pool

recovery pop does not look like og pop, looks like survivor pop instead

Question 16

effects of selection

Answer 16

dec freq of alleles that reduce fitness

dominant mutant alleles dissapear quickly

Question 17

positive selection

Answer 17

heteros have advantage bc wider spectrum of enzyme activity or disease resistance

CFTR mutations = typhoid fever, cholera, tuberculosis
malaria = beta hemoglobin
plague = HFE mutations

Question 18

founder effects

Answer 18

i.e EVS prominent among Pennsylvania Amish

-high mutant frequency (q) + consanguinity