Random Flashcards
5 Hardy Weinberg assumptions
(17)
- Random mating (no assortative/dissortative mating)
- No mutation
- No selection
- No genetic drift
- No migration
In randomly mating populations what are the expected frequencies of homozygous (AA), homozygous (TT), and heterozygous (AT)?
(17)
Homozygous (AA) = p^2
Homozygous (TT) = q^2
Heterozygous (AT) = 2pq
what is assortative mating?
(17)
genotypically similar individuals mate
leads to a higher population homozygotes for the trait individuals are choosing to mate with.
what is dissortative mating?
(17)
genotypically dissimilar individuals mate.
causes a higher amount of heterozygotes in population.
what is inbreeding?
(17)
mating of close relatives.
leads to more homozygous for deleterious recessive alleles (inbreeding depression)
what is the inbreeding coefficient formula?
what is the inbreeding coefficient with no inbreeding?
what is the inbreeding coefficient if there is not heterozygotes?
(17)
F = 1- H observed/2pq
no inbreeding - F = 0
no heterzzygotes - F = 1
what is it called when a subset of individuals creates its own population?
(17)
Founder effect
what is it called when changes in allelic frequencies over generations is caused by random sampling from a small population?
(17)
Genetic drift
In an infinite population does allele frequency change over time?
(17)
No
What happens in relation to change of Allele frequency when you make the population smaller?
(17)
When population size decreases the changes in allele frequency are much greater and there is more chance of population going to fixation or dying.
Is genetic drift biased?
(17)
No it is unbiased.
what is directional selection?
(17)
Allele for one feature are selected for and the other against. Distribution shift one way or the other
Example: when an organism environment changes and leads to an increase in frequency of some alleles over others.
What is disruptive selection?
(17)
Two opposite phenotypes are selected for and the intermediate is selected against.
example: tail length. short tails help get away from predators, long tails help with balance. medium tails have no benefit
What is stabilising selection?
(17)
When the intermediate phenotype is selected for and two opposites are selected against. This leads to a reduction in variation. Most common type of selection.
What is fitness?
(17)
Measure of how good an organism is at surviving and reproducing offspring.
By convention assign 1 to the genotype with the highest fitness.
