Genetics II - Population Genetics

Question 1

Define allele

Answer 1

A single copy of a gene

Question 2

Define genotype

Answer 2

The pair of alleles in an individual

Question 3

Define polygenic traits?

Answer 3

Characteristics influenced by more than one gene

Question 4

Define gene interaction

Answer 4

A single trait controlled by 2 or more genes
- each of which has multiple alleles within a population of individuals.

Question 5

Define monomorphic gene

Answer 5

A gene which exists as a single allele in a population
- so all individuals are automatically homozygous for it as the 2 copies are the same.

Question 6

Define polymorphic gene

Answer 6

A gene that has 2 or more allelic variants within a population
- homozygous: both copies same
- heterozygous: copies differ

Question 7

What is population genetics?

Answer 7

Study of genes and genotypes in a population

Question 8

Define gene pool

Answer 8

All of the alleles for every gene in a given population

Question 9

What are single nucleotide polymorphisms (SNPs)?

Answer 9

Smallest type of genetic change in a gene

Question 10

How do you calculate allele frequency?

Answer 10

(no. of copies of a specific allele in a population) / (total number if all alleles for that gene in a population)

Question 11

How do you calculate genotype frequency?

Answer 11

(no. of individuals with a particular genotype in a population) / (total number of individuals in a population)

Question 12

What is the Hardy-Weinberg equation?

Answer 12

Sums all genotype frequencies for a given gene in a population.

Question 13

What is the mathematical Hardy-Weinberg equation?

Answer 13

p^2 + 2pq + q^2 = 1

Question 14

What does the Hardy-Weinberg law state?

Answer 14

That allele and genotype frequencies in population will remain constant from generation to generation in the absense of other evolutionary influences.

Question 15

What are the conditions for Hardy-Weinberg Equilibrium?

Answer 15

• no new mutations occur
• no natural selection occurs
• pop so large that allele frequencies do not change due to random sampling error
• no migration changes between diff pops
• random mating occurs

Question 16

Do any populations meet the conditions for Hardy-Weinberg Equilibrium?

Answer 16

None so an evolution mechanism is at work

Question 17

Define Microevolution

Answer 17

Changes in a population’s gene pool from generation to generation

Question 18

Give examples of genetic variation

Answer 18

• mutations
• gene duplication
• horizontal gene transfer

Question 19

Why do microevolutionary changes occur?

Answer 19

• new genetic variation produced
• actions of evolutionary mechanisms that alter the prevalence of an allele/genotype

Question 20

Give examples of evolutionary mechanisms

Answer 20

• natural selection
• random genetic drift
• migration
• non-random mating

Question 21

How does natural selection contribute as an evolutionary mechanism?

Answer 21

Results in changes in populations of living organisms that promote their survival and reproduction in a particular environment - resulting in adaptation.