Chapter Eighteen: Population Genetics

Question 1

…is the study of genes and genotypes in populations, and how they can change over time

Answer 1

Population Genetics

Question 2

Population Genetics depends on the existence of genetic…

Answer 2

variation

Question 3

….(many forms) refers to a trait that shows more than one phenotype

Answer 3

Polymorphism

Question 4

To be considered polymorphic, rare alleles must be present at a frequency of >…

Answer 4

> 1%

Question 5

Polymorphisms may be due to:
1. …of a region of a gene
2. …of a region of a gene
3. Change in a single… (substitution mutation) (Single-Nucleotide Polymorphism or snips)

Answer 5

Deletion
Duplication
nucleotide

Question 6

snips represent …% of all variation in human DNA

Answer 6

90

Question 7

To calculate allergic frequencies, it is necessary to know the…of all individuals in the population

Answer 7

genotypes

Question 8

Equation for finding the frequency of allele:

Answer 8

of certain allele / #total allele

Question 9

what two letters are typically used to symbolize two allelic frequencies?

Answer 9

p and q

Question 10

…frequencies are the frequencies or proportions of the different genotypes

Answer 10

Genotypic

Question 11

In 1908, what two people both independently proposed the conditions under which allelic and genotypic frequencies would remain constant (equilibrium)

Answer 11

Hardy and Weinberg

Question 12

Under equilibrium, both allelic and genotypic frequencies would remain constant, and the genotypic frequencies would depend upon or could be calculated from what frequencies?

Answer 12

allelic frequencies

Question 13

What are the five Hardy Weinberg Equilibrium Conditions?

Answer 13

1. No mutations
2. No natural selection
3. No migration between populations
4. Infinite population size
5. Random Mating

Question 14

Populations are…in Hardy-Weinberg Equilibrium and meet all 5 conditions for equilibrium

Answer 14

rarely

Question 15

Hardy-Weinberg Equilibrium is useful to show the conditions under which allelic and genotypic frequencies will not remain constant but will…

Answer 15

Change

Question 16

The change in allelic frequencies over time is…

Answer 16

microevolution

Question 17

mutations may be important in providing the variation for…but is not important in directly changing allele frequencies

Answer 17

natural selection

Question 18

…occurs when one genotype has an advantage that allows the individuals with that genotypes to survive better and leave more offspring than other genotypes

Answer 18

natural selection

Question 19

natural selection is usually defined with…

Answer 19

fitness

Question 20

the maximum fitness is…

Answer 20

1

Question 21

Is a high fitness good or bad?

Answer 21

good

Question 22

a positive selection coefficient means that natural selection works…the genotype

Answer 22

against

Question 23

If natural selection is operating, it means that some genotypes are not leaving as many offspring and genotypic frequencies will change. This is also known as…

Answer 23

Microevolution

Question 24

If the dominant or recessive genotype is at a selective disadvantage, the frequency of the allele producing that genotype will…overtime

Answer 24

decrease

Question 25

Genetic variation produces a range of…, usually in a normal distribution

Answer 25

phenotypes

Question 26

If both extremes in phenotype are selected against, …will force the phenotype to become less variable

Answer 26

Stabilizing Selection

Question 27

If intermediate phenotypes are selected against, …produces two phenotypes

Answer 27

Disruptive Selection

Question 28

What kind of selection occurs when two alleles are maintained in a population?

Answer 28

Balancing Selection

Question 29

Heterozygote advantage occurs if the heterozygote has the…fitness

Answer 29

highest

Question 30

What kind of selection occurs when individuals with a rare genotype have a higher fitness than individuals with a more common genotype?

Answer 30

Negative frequency-dependent selection

Question 31

What kind of selection occurs when certain genotypes have an advantage over other genotypes of the same sex, with respect to reproduction?

Answer 31

Sexual Selection

Question 32

…refers to the changes in allelic frequencies due to random/chance events

Answer 32

Random Genetic Drift

Question 33

What kind of effect occurs when a small number of individuals found a new population?

Answer 33

Founder Effect

Question 34

What kind of effects occur when populations that are usually large, experience temporary decreases?

Answer 34

Bottleneck Effects

Question 35

The neutral theory of evolution believes the contribution of each gene to the overall fitness of the individual is…

Answer 35

small

Question 36

What refers to the movement of individuals from one population to another?

Answer 36

Migration

Question 37

As individuals move, they carry their alleles with them, this is called…

Answer 37

Gene flow

Question 38

Mating must be…if allele frequencies are not to change

Answer 38

random

Question 39

If mating with one genotype is preferred, the alleles making up that genotype will…

Answer 39

increase

Question 40

What kind of mating occurs when individuals tend to mate with others with a similar phenotype?

Answer 40

Positive Assortative Mating

Question 41

What kind of mating occurs when mating between different phenotypes is preferred?

Answer 41

Negative Assortative Mating

Question 42

Inbreeding…refers to the decrease in fitness brought about by the production of deleterious homozygous phenotypes as a result of inbreeding

Answer 42

depression