Population genetics (notes) 4b

Question 1

Population

Answer 1

Interbreeding groups of individuals that belong to the same species and live within a restricted geographical area

Question 2

Population genetics

Answer 2

Concequences of mendelian genetics in a population- a shift from indiidual to population

Question 3

The frequency of an—— in a population is often—– as the ration in a single cross

Answer 3

• an allele
• not the same

Question 4

Darwin’s four conditions for evolution by natural selection (4)

*If these conditions are met, we will see change in allele frequencies and evolution

Answer 4

1. Individuals within a species vary
2. Some variation is passed to offsprings (Heritable)
3. More offspring are produced than can survive and or/reproduce
4. Survivial and reproduction is not random but related to phenotypic variation (gives certain individuals advantage

Question 5

If darwin’s four conditions are met:

Answer 5

we will see changes in allele frequencies and evolution

Question 6

Evolution by natural selection will not occur if (3)

Answer 6

• there is no variation in species
• the variation is not inheritable
• Variation is heritable but has no fitness consequence

Question 7

If there are no gene flow or variation being introduced into a population, and no variation being selected for we will….

Answer 7

not see any change in genetic variation

Question 8

What is our null hypothesis for evolution?

Answer 8

There will be no change in allele frequencies over time

Question 9

A population to be in abscence of evolution (no change in allele frequencies) has to have these conditions (5):

Answer 9

1. A single locus with 2 alleles that does not change between generation (ie: no mutations/we do not introduce any new alleles)
2. No gene flow
3. Population is infinite
4. Natural selection does not affect the alleles considered individuals have same fitness
5. Random mating

Question 10

Gene flow types (2)

Answer 10

Immigration+migration

Question 11

Why population has to be very big?

Answer 11

This eliminates the effect of random processes that could change allele frequencies (ie: volcanic erupted)

Question 12

genetic drift (2)
+ why its required for HWE

Answer 12

Allele frequencies can change by chance alone given the number of matings that can occur when you have a low number of individuals compared to a large number of individuals

the drifting of the frequency of an allele relative to that of the other alleles in a population over time as a result of a chance or random event

Question 13

Random mating

Answer 13

regardless of phenotype at the locus of interest, all diploid individuals have the same fitness

Question 14

elaborate what “natural selection does not affect the alleles considered” mean in HWE (3)

do not say there is no fitness consequence u dumbass

Answer 14

Probability of surviving to breed is the same
mating and fertilizing ability is the same

Question 15

Hardy weinberg equlibrium equations

Answer 15

P+q=1

Question 16

Probability of two independent events occuring together is the —- of their individual probabilities

Answer 16

product

Question 17

Frequencies of the three genotypes formula:

Answer 17

1. AA-p^2
2. Aa-2pq
3. aa-q^2

Question 18

Because the gametes are haploid and mix randomly, if there is no selection at the genotype level:

Answer 18

all gametes goes back into gene pool

Question 19

under hardy weinberg the caculated genotype frequency with p^2+2pq+q^2 will always

Answer 19

be the same

Question 20

How do you tell if this population is in HWE?

Answer 20

1. Calculate allele frequency
2. Calculate expected genotype frequency
3. Calculate the expected numbers under HWE using the expected genotype frequency and total population number
4. Chi-sqaure test with given actual amount

Question 21

In general in a sample of n individuals the frequency of an allele is

Answer 21

The number of occurences of the allele divided by twice the number