Genetic Drift

Question 1

When we consider genetic drift, what HW assumption is being violated?

Answer 1

Population size is infinate

Question 2

Define genetic drift

Answer 2

A change in allele frequencies across generations due to random error in the sampling of gametes

Question 3

On average, does genetic drift increase or decrease variation within a population?
Why?

Answer 3

Decrease of genetic variation because it involves random changes in allele frequencies, which can lead to the loss of rare alleles and the fixation of more common ones, ultimately reducing the overall genetic diversity within a population, especially in small populations where the effects of chance are more pronounced.

Question 4

The rate of genetic drift per generation is related to what?

Answer 4

The population size

Question 5

Are low frequency or high frequency alleles most likely to be lost by genetic drift?

Answer 5

low frequency alleles

Question 6

What is the probability of fixation of an allele in a population? Given this, what is the probability of fixation of a new mutation? Does this calculation use the census or effective population size?

Answer 6

The probability of fixation of an allele is equal to the initial frequency of the allele

The probability of fixation of a new mutation is 1/(2N)

Question 6

Genetic drift reduces diversity within populations, but increases diversity between populations? Explain

Answer 6

random chance events can cause certain alleles to become more or less frequent in a population, potentially leading to the loss of some alleles altogether, while simultaneously increasing diversity between populations as different populations experience independent random fluctuations in allele frequencies, resulting in distinct genetic compositions even if they were originally the same population

Question 6

True/False: Given a large number of populations, genetic drift will change the mean frequency of alleles averaged across all populations

Answer 6

false
-on average, genetic drift does not change the mean allele frequency among populations

Question 6

What variable impacts the rate of change in heterozygosity in a population over time?

Answer 6

Nonrandom mating

Question 6

Does genetic drift increase or decrease heterozygosity within a population over time?

Answer 6

It decreases heterozygosity over time

Question 6

Does genetic drift only impact small populations?

Answer 6

genetic drift can occur in populations of any size, it has a significantly greater impact on small populations

Question 6

What is a founder effect? How does this concept relate to genetic drift?

Answer 6

change in allele frequencies that occurs during the establishment of a new population due to sampling error in drawing founders from the source population
=a population bottleneck that results from colonization
=a form of genetic drift