Lecture 14 - Case Studies in Population Genetics Flashcards
What is population genetics?
The study of genetic variation within populations.
What are the four key processes that change the frequency of alleles in a population?
- Gene flow
- Mutation
- Genetic drift
- Natural selection
What two processes increase levels of diversity within a population?
- Gene flow
- Mutation
What two processes decrease levels of diversity within a population?
- Genetic drift
- Natural selection
What is gene flow?
The transfer of allelic variation from one population to another via migration
What is genetic drift?
Random fluctuations in allele frequency due to chance events.
What is natural selection?
The process whereby organisms better adapted to their environment contribute disproportionately to the next generation.
Describe Microsatellite loci.
- Codominant
- Abundant in most genomes
- Highly variable
- Easy to simultaneously screen multiple loci
Describe a case study on microsatellite loci.
Microsatellite variation in trout populations from rivers in SW England.
- Fish from 34 rivers
- Screened for variation at 19 microsatellite loci
What does Cornwall have a history of?
Mining tin
Which two rivers in Cornwall have the highest levels of toxic metals?
Red River and Hayle
What four main metal pollutants are found in Cornish rivers?
- Copper
- Arsenic
- Zinc
- Nickel
What fish were found to be resistant to toxic metal in rivers?
Brown trout
What was found about populations of fish in rivers containing metal?
They had low genetic diversity
What can be said about the genetic structure in bigger catchments?
Have less structure.
Which metal is found in highest levels in River Hayle?
Zinc
Describe Godolphin.
- 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
When did the River Hayle split from upstream or downstream?
1860 AD
What is gene diversity?
A measure of how variable a sample is
What is allelic richness?
The average number of alleles per locus.
Give the four categories for the correlation of geographic and genetic distances.
1) Isolation by distance
2) Panmixia
3) Small, isolated populations
4) Local gene flow
What is isolation by distance?
The further apart the two populations are, the less likely that there is gene flow between them.
What is panmixia?
Fish will go into any river to breed.
Allele frequencies are constant.
What is the most important process for genetic diversity for brown trout in Cornish rivers?
Genetic drift
