Mendelian Genetics of Populations: Quantification of Variation (lect 06)

Evolution

genetic changes in population over time

Populations

all the individuals of one species that are present and interbreeding at a specific geographic location

Individuals

The population evolves not ____

Gene pool

all gene copies in the population

Evolution

is change in the gene pool composition

How populations evolve

“population genetics” study of how frequencies of alleles and genotypes change

Relative genotype frequencies

Gene pools can be described with … (1)

Relative allele frequencies

Gene pools can be described with …

allele frequencies → genotype frequencies

The Hardy-Weinburg modelrelates ___ frequencies to ____ frequencies of an idealized population

Hardy-Weinberg Assumptions

The organism are

• Diploid organisms

• sexual reproduction

• non-overlapping generation (all parents die after reproduction)

• no sex-linked alleles

The population allele frequencies that do not change (HWM)

• No mutation

• No selection

• No gene flow (migration)

• No genetic drift (i.e. population size is effectively infinite)

• Mating is random (all individuals have the same probability of mating with any other individual)

Genetic frequencies that model the HWM

• Population allele frequencies are not changing (= no evolution)

• No mutation

• No selection

• No gene flow (migration)

• No genetic drift (i.e. population size is infinite)

• Population IS mating randomly

Genetic frequencies that do NOT model the (HWM)

• The population is evolving (allele frequencies are changing)

• There is Mutation

• Selection

• Gene flow (migration)

• Genetic drift (i.e. finite-population size, not infinite)

• The population has non-random mating

The population is in equilibrium

if allele frequencies p and q do not change over time

produce genotype frequencies

if mating is random, the allele frequencies will …

Population is Hardy-Weinberg equilibrium

if the population is in equilibrium & produces genotype frequencies