Lecture 14 - Case Studies in Population Genetics

Question 1

What is population genetics?

Answer 1

The study of genetic variation within populations.

Question 2

What are the four key processes that change the frequency of alleles in a population?

Answer 2

• Gene flow
• Mutation
• Genetic drift
• Natural selection

Question 3

What two processes increase levels of diversity within a population?

Answer 3

• Gene flow

- Mutation

Question 4

What two processes decrease levels of diversity within a population?

Answer 4

• Genetic drift

- Natural selection

Question 5

What is gene flow?

Answer 5

The transfer of allelic variation from one population to another via migration

Question 6

What is genetic drift?

Answer 6

Random fluctuations in allele frequency due to chance events.

Question 7

What is natural selection?

Answer 7

The process whereby organisms better adapted to their environment contribute disproportionately to the next generation.

Question 8

Describe Microsatellite loci.

Answer 8

• Codominant
• Abundant in most genomes
• Highly variable
• Easy to simultaneously screen multiple loci

Question 9

Describe a case study on microsatellite loci.

Answer 9

Microsatellite variation in trout populations from rivers in SW England.

• Fish from 34 rivers
• Screened for variation at 19 microsatellite loci

Question 10

What does Cornwall have a history of?

Answer 10

Mining tin

Question 11

Which two rivers in Cornwall have the highest levels of toxic metals?

Answer 11

Red River and Hayle

Question 12

What four main metal pollutants are found in Cornish rivers?

Answer 12

• Copper
• Arsenic
• Zinc
• Nickel

Question 13

What fish were found to be resistant to toxic metal in rivers?

Answer 13

Brown trout

Question 14

What was found about populations of fish in rivers containing metal?

Answer 14

They had low genetic diversity

Question 15

What can be said about the genetic structure in bigger catchments?

Answer 15

Have less structure.

Question 16

Which metal is found in highest levels in River Hayle?

Answer 16

Zinc

Question 17

Describe Godolphin.

Answer 17

• Several deep wet mines
• Water pumped out of them to avoid flooding, effort to remove water from mines
• Spikes in concentration of toxic metals, still continuing today

Question 18

When did the River Hayle split from upstream or downstream?

Answer 18

1860 AD

Question 19

What is gene diversity?

Answer 19

A measure of how variable a sample is

Question 20

What is allelic richness?

Answer 20

The average number of alleles per locus.

Question 21

Give the four categories for the correlation of geographic and genetic distances.

Answer 21

1) Isolation by distance
2) Panmixia
3) Small, isolated populations
4) Local gene flow

Question 22

What is isolation by distance?

Answer 22

The further apart the two populations are, the less likely that there is gene flow between them.

Question 23

What is panmixia?

Answer 23

Fish will go into any river to breed.

Allele frequencies are constant.

Question 24

What is the most important process for genetic diversity for brown trout in Cornish rivers?

Answer 24

Genetic drift