populations genetics and hardy-Weinberg equilibrium

populations

- a group of individuals of a particular species occupying a definite space in which the individuals interact, interbreed, and exchange genetic materials

- shares a common gene pool

- is the smallest unit that can evolve—in other words, an inidividual can't evolve.

the gene pool

- species in a population have a shared?

- all of the alleles of all individuals in a population

mutation

genetic drift

selection

gene flow

non-random mating

(5) types/agents of evolutionary change

mutation

- creates variation

- changes DNA sequence, changes amino acid sequence, and changes proteins

- Small ____ creep into populations over time. Some are helpful, some harmful, and many are neutral but may be beneficial or harmful later.

- increase genetic variation in a population.

gene flow

- Some individuals from a population of brown beetles may have joined a population of green beetles. What would make the genes for brown beetles more frequent in the green beetle population?

bottleneck effect

- when a large population is drastically reduced by a disaster and lowers variation.

- also narrows the gene pool.

natural selection

- survival & reproduction due to changing environmental conditions.

Hardy-Weinberg equilibrium

- "A fundamental principle in population genetics stating that the genotype frequencies and gene frequencies of a large, randomly mating population remain constant provided immigration, mutation, and selection do not take place." American Heritage Dictionary

- usually results in evolution

- Godfrey Harold Hardy (1877-1947)

- Wilhelm Weinberg (1862-1937)

No Selection

No Mutation

No Migration

Large Population

Random Mating

(5) ASSUMPTIONS OF HARDY-WEINBERG EQUILIBRIUM

No natural selection

- if some individuals survive and reproduce at a higher rate than others, then their offspring will carry those genes and the frequency will change for the next generation.

No migration

- Immigrants can change the frequency of an allele by bringing in new alleles to a population.

No mutations

- if alleles change from one to another, this will change the frequency of those alleles

Large population size

- small populations have fluctuations in allele frequencies (e.g., fire, storm).

POPULATION GENETICS

The study of the rules governing the maintenance and transmission of genetic variation in natural populations.

Random mating

- if certain traits are more desirable, then individuals with those traits will be selected and this will not allow for random mixing of alleles.

1.0 = p + q

Determining the Allele Frequency using Hardy-Weinberg:

p

= Frequency of “A” allele

q

frequency of “a” allele

p

is the frequency of the dominant allele.

q

is the frequency of the recessive allele.

p²

is the frequency of individuals with the homozygous dominant genotype.

2pq

is the frequency of individuals with the heterozygous genotype.

q²

is the frequency of individuals with the homozygous recessive genotype.