Population Genetics

Question 1

Genotypic Frequency

Answer 1

• Proportion of a particular genotype within a population.

Question 2

Mendelian Population

Answer 2

• A group of interbreeding, sexually reproducing individuals that have a common set of genes.

Question 3

Allelic Frequency

Answer 3

• Proportion of a particular allele within a population.

Question 4

Genetic Rescue

Answer 4

• Introduction of new genetic variation into an inbred population in an effort to improve the health of the population and better ensure its long-term survival.

Question 5

Gene Pool

Answer 5

• Set of all genes in a population.

Question 6

Hardy-Weinberg Law

Answer 6

– Principle of population genetics stating that if a population is large, randomly mating, and not affected by mutation, migration, or natural selection, then allelic frequencies of a population do not change and the genotypic frequencies stabilize after one generation in the proportions p2 (the frequency of AA), 2pq (the frequency of Aa), and q2 (the frequency of aa), where p equals the frequency of allele A and q equals the frequency of allele a.

Question 7

Hardy-Weinberg Equation

Answer 7

p2 + 2pq + q2 = 1

Question 8

Hardy-Weinberg Equilibrium

Answer 8

• Frequencies of genotypes when the conditions of the Hardy–Weinberg law are met.

Question 9

Degrees of freedom for a chi-square test of Hardy-Weinberg equilibrium

Answer 9

The number of genotypes – the number of alleles

Question 10

Inbreeding

Answer 10

 - A form of non-random mating; preferential mating between related individuals.

Question 11

Inbreeding Depression

Answer 11

• Decreased fitness arising from inbreeding; often due to the increased appearance of lethal or deleterious traits with inbreeding.

Question 12

Non Random Mating

Answer 12

• When the probability that two individuals in a population will mate is not the same for all possible combinations of genotypes.

Question 13

Sampling Error

Answer 13

• Deviations from expected ratios due to chance when the sample size is small.

Question 14

Genetic Drift

Answer 14

• Change in allelic frequencies due to a sampling error.

Question 15

Migration

Answer 15

• Movement of genes from one population to another; also called gene flow.

Question 16

Mutation As An Evolutionary Force

Answer 16

-Creates new genetic variation in a gene pool. 

Question 17

Founder Effect

Answer 17

• Sampling error that results from the establishment of a population by a small number of individuals; leads to genetic drift.

Question 18

Effective Population Size

Answer 18

• Effective number of breeding adults in a population; influenced by the number of individuals contributing genes to the next generation, their sex ratio, variation between individuals in reproductive success, fluctuations in population size, age structure of the population, and whether mating is random.

Question 19

Genetic Bottleneck

Answer 19

• Sampling error that arises when a population undergoes a drastic reduction in size; leads to genetic drift.

Question 20

Selection Coefficient

Answer 20

• Measure of the relative intensity of selection against a genotype; equals 1 minus W (fitness value).

Question 21

Directional Selection

Answer 21

• Selection in which one allele or trait is favored over another.

Question 22

Overdominance

Answer 22

• Selection in which the heterozygote has higher fitness than either homozygote; also called heterozygote advantage.

Question 23

Fitness

Answer 23

• Reproductive success of a genotype relative to that of other genotypes in a population.

Question 24

Natural Selection

Answer 24

• Differential reproduction of individuals with different genotypes.

Question 25

Underdominance

Answer 25

• Selection in which the heterozygote has lower fitness than either homozygote.

Question 26

Fixation

Answer 26

• When one allele reaches a frequency of 1 in a population, at which point all individuals in the population are homozygous for one allele.