Population Genetics & Natural Selection Flashcards
Localised group of individuals of the same species
Population
Total aggregate of genes (and alleles) in the population at one time
Gene pool
Why do we need to estimate the frequencies of genotypes in a population?
- to predict how many people will inherit a genetic disease
- to estimate a proportion for how many people are carriers for the disease
This is a random change in allele frequencies due to sampling error over generations
- this removes genetic diversity from a population
Random Genetic Drift
This is when a population reduction occurs due to random chance effects. Resulting in a change of allele frequencies,
Bottleneck Effect
When a new population is founded (either due to migration/genetic drift) but new population is NOT representative of original population.
Founder Effect
This is a selection that favours medium sized individual. It reduces variation but does not change mean
Stabilising Selection
This is a selection that favours one extreme. Which changes the mean value towards one extreme.
Directional Selection
This is a selection that favours two extremes which produces two peaks in the mean/graph.
Disruptive Selection
This selection occurs when one phenotype is more physically attractive than the other. These attractive features serve no practical purpose other than to attract a potential mate, and a way to pass genes more quickly and conveniently.
Sexual Selection
This selection occurs when fitness of a phenotype is dependent on its frequency relative to other phenotypes in a given population.
Frequency dependent selection
This is the gradual geographic change in genetic or phenotypic composition.
Cline
What are the 2 factors that affect genetic diversity?
Mutation and Migration
