What is a population?
An interbreeding group of individuals that belong to the same species and live within a restricted geographical area
Allele frequency in a population vs a single cross
often not the same
Evolution by natural selection will not occur when…
there is no variation, variation is not heritable, or there is no fitness consequence due to variation
In the absence of evolution…
Variation should remain unchanged over time
Null hypothesis for evolution
No change in allele frequencies over time
Hardy Weinberg assumptions
-no mutation
-no gene flow
-very large population size (infinite in theory)
-same fitness (no natural selection)
-random mating
p
Frequency of allele A
q
Frequency of allele a
p+q
=1
p^2
Probability of A/A genotype in HWE
pq
Probability of A/a genotype in HWE
q^2
Probability of a/a allele in HWE
How many generations for a population to achieve HWE with all conditions met?
One
F(A) = p^2 + 0.5(2pq)
Used to calculate frequency of allele A not in HWE
F(a) = q^2 + 0.5(2pq)
Used to calculate frequency of allele a not in HWE
If a population is not in HWE is it evolving?
Not necessarily- a sustained change in allele frequencies would be needed to prove evolution is occurring
