7.4: population genetics

Question 1

genetic diversity

Answer 1

result of a large number of variants in each gene for each polygenic trait

Question 2

mutation

Answer 2

one of main sources of genetic variation; three types: detrimental, neutral, beneficial

Question 3

detrimental/deleterious mutations

Answer 3

highest frequency, are eliminated

Question 4

neutral mutations

Answer 4

no immediate effect, may provide advantage if future environment changes drastically
- remains as evolutionary ‘back-up’

Question 5

beneficial mutations

Answer 5

selected, are highly likely to be passed on

Question 6

population genetics study

Answer 6

study of how a population changes over time, and leads to the evolution of species
- is quantitative study, analyses distribution of genetic variations
- factors that attribute to increases/decreases in allele frequency studied

Question 7

factors that cause changes in allele frequency

Answer 7

• selective pressures
• sexual selection
• mutation
• genetic drift
• gene flow

Question 8

selective pressures

Answer 8

causes changes in allele frequency due to variations; alleles that make individuals more suited to the environment increase

Question 9

sexual selection

Answer 9

changes allele frequency through ensuring the most successful maters’ genes remain in the gene pool

Question 10

mutation

Answer 10

leads to formation of new alleles, due to changes in DNA that arise during gametogenesis
- both useful + deleterious errors passed on

Question 11

genetic drift

Answer 11

changes in allele frequency due to random chance, introduces variety
- bottleneck effect: genetic drift due to natural disaster
- founder effect: isolation of few individuals through geographic means

Question 12

gene flow

Answer 12

changes in allele frequency due to mixing of new individuals into population
- occurs through immigration/emigration

Question 13

‘fixed’ allele

Answer 13

the only remaining allele in the population, having outcompeted all other alleles
- unusual, most variants/alleles give small benefit or no benefit

Question 14

genetic stability

Answer 14

occurrence in which all individuals have same reproductive capacity and fitness
- any change that disrupts this will result in change in allele frequencies

Question 15

mendel’s findings

Answer 15

pea model:
- each parents donates one allele for every gene to offspring, therefore offspring have two alleles for each gene
- expression of dominant + recessive alleles

Question 16

darwin’s findings

Answer 16

natural selection as primary force for evolution: if gene gives advantage, most likely to be passed on to next generation