Introduction to Population Genetics Flashcards
What is a locus?
The physical position of a gene or marker along a chromosome
What is a polymorphism?
A gene or phenotype with more than one form
What do population genetics study?
The frequencies of alleles in a population
What is the frequency equation of a gene that has two alleles?
p + q = 1
What is the Hardy-Weinberg equilibrium?
p^2:2pq:q^2
What assumptions are made for the Hardy-Weinberg equilibrium?
Random mating
No natural selection
A large population size
No migration
No mutation
Why is HWE useful?
It provided description of how genetic variation is maintained
Departures from HWE mena that some assumptions are not met
Useful in medical genetics
What are the steps to calculate HWE?
Step 1 - estimate allele frequency
Step 2 - calculate the expected genotype frequencies under HWE
Step 3 - calculate the expected genotype counts in the sample
Step 4 - calculate the chi-square statistic
What is the chi-squared value a measure of?
Goodness of fit
How are degress of freedom calculated for chi-squared?
Number of genotypes - number of parameters estimated - 1
What is expected heterozygosity?
A measure of the level of variability at a locus
