Population Genetics- Lecture 49

Question 1

Define population genetics.

Answer 1

the application of genetic principles to entire populations of organisms

Question 2

What is allele frequency and how is it calculated?

Answer 2

percentage of a particular allele with respect to the total alleles in a population
p- allele frequency of A
q- allele frequency of a
p-q = 1

Question 3

What is gene frequency and how can it be calculated?

Answer 3

percentage of individuals in a population with a particular genotype
p^2 - genotype frequency of major homozygotes (AA)
2pq - genotype frequency of heterozygotes (Aa)
q^2 - genotype frequency of minor homozygotes (aa)
p^2 + 2pq + q^2 = 1

Question 4

List the factors that could result in deviation of a population from HW equilibrium.

Answer 4

new mutations
gene flow (in or out migration)
natural selection
genetic drift (bottleneck or founder's effect)
non-random mating (assortative mating or inbreeding/consanguinity)

Question 5

Describe natural selection.

Answer 5

presence of allele may increase or decrease reproductive fitness (health) of an individual, so genotypes that promote survival are favored and passed down to next generation

Question 6

Describe genetic drift.

Answer 6

in populations that have relatively small number of unrelated founder individuals, allele frequencies can be skewed by chance so that some alleles become more common in the population by chance (not selection)

Question 7

What is a population bottleneck?

Answer 7

an event that drastically reduces the size of the population, leading to less gene pool variation

Question 8

What is the founder effect?

Answer 8

a subtype of genetic drift

leading to specific disease alleles becoming more prevalent in certain populations due to small group migration

Question 9

Describe assortative mating.

Answer 9

selecting mates based on ethnicity, culture, physical limitations, education, stature, and/or geographical location

Question 10

Describe the effects of consangiunity (inbreeding).

Answer 10

normally in small sub-populations
increases minor allele frequency
increases homozygosity
increased risk of recessive disease

Question 11

What is population stratification?

Answer 11

phenomenon where there are distinct subpopulations that have different allele frequencies

Question 12

What are AIMS?

Answer 12

ancestry informative markers

polymorphic genetic alleles that vary significantly across populations from different geographic origins