Chapter 4: Hardy-Weinberg Equilibrium Flashcards
from Hardy-Weinberg Equilibrium indicates that Evolution is happening
Deviation
Deviation from Hardy-Weinberg Equilibrium indicates that ______ is happening
Evolution
What happens in Hardy-Weinberg across a Genome?
Some loci might be undergoing natural selection and become out of HW equilibrium, while the rest of the genome remains in HW equilibrium (or bein in HW equilibrium at other loci)
How can you tell whether a population
is out of HW Equilibrium? (Calculation)
- Perform HW calculations (population - in / out )
- Then apply statistical tests (deviation - significant / not)
How can you tell whether a population
is out of HW Equilibrium? (Predict)
- When allele frequencies are changing across generations
- When you cannot predict genotype frequencies from allele frequencies
A test that can be used to determine if a population is significantly different from the expectations of HW equilibrium
Goodness-of-fit test
Goodness-of-fit test symbol
x^2
Goodness-of-fit test Formula
x^2 = ∑ (Oi - Ei)^2 / Ei
If the test statistic > than the critical value
- null hypothesis can be rejected
- alternative hypothesis can be accepted
H0 =
there is no difference between the distribution
H1 =
there is a difference between the distributions
If the test statistic < than the critical value
the null hypothesis cannot be rejected
If the result come out not significantly different from HW equilibrium, what can we conclude?
- does not necessarily mean that genetic drift is not happening
- we cannot conclude that genetic drift is happening
One generation of ____ ____ could put a population back into Hardy Weinberg Equilibrium
Random Mating
Examples of Deviation from Hardy-Weinberg Equilibrium
- Genetic Drift
- Negative Selection
- Heterozygote Advantage (or Overdominance)
- Selection appears to be favoring aa
