Post on 21-Dec-2015
Hardy Weinberg
Hardy Weinberg refers to
Populations
Hardy Weinberg Equilibrium
•What it is?
•A way to measure evolution in a population
•Allele frequency will not change from generation to generation if a population is not evolving.
These are your alleles
Genotype?
B b
Phenotype?
What is the allele frequency
in the room?
Let’s set up a data table to record our allele frequencies.
Let’s Reproduce...Meiosis Anyone?
Then into the gene pool
This is This is
more likemore like spawningspawning
What is our new allele frequency?
1. Natural Selection2. Calculate survivor allele frequency3. SURVIVORS only...Reproduce4. Next generation
H-W Equilibrium says Allele Frequency will remain the same from generation to
generation...DID IT?
Oh Wait...
Hardy Weinberg Conditions
1. No mutation
2. Random Mating
3. Large Population
4. No Natural Selection
5. No emigration/immigration
Science Practice 1
•The student can use representations and models to communicate scientific phenomena and solve scientific problems.
•Model : Reproductive isolation.
•Model: genetic drift
•Model: non-random mating
•Model: mutation
•Model: emigration/immigration
How do we use the H-W Formula?
•p2 + 2pq + q2 = 1
1919
Hardy-Weinberg describes the status quo and Hardy-Weinberg describes the status quo and provides a way to describe change.provides a way to describe change.
5 conditions must be met:5 conditions must be met:
Allele frequencies wonAllele frequencies won’’t change if…t change if…
1. The population is large1. The population is large
2. Mating is random2. Mating is random
3. There is no mutation 3. There is no mutation
4. No immigration or emigration4. No immigration or emigration
5. There is no selection5. There is no selection
2020
All the alleles in a population must All the alleles in a population must equal 100%equal 100%
Say A and a are the alleles at a locusSay A and a are the alleles at a locus
Diploid organisms have 2 lociDiploid organisms have 2 loci
p = the frequency of Ap = the frequency of A
q = the frequency of aq = the frequency of a
So the frequency of p + q must equal 100% So the frequency of p + q must equal 100% or 1.0or 1.0
2121
Frequency of possible combinations of p Frequency of possible combinations of p and q for diploid organismsand q for diploid organisms
• (p+q) (p+q) =(p+q) (p+q) =
pp22 + 2pq + q + 2pq + q22
•In a population of 1000 individuals, 360 of the individuals have an attached earlobe, a recessive trait. This population is in Hardy Weinberg equilibrium. How many individual are heterozygous for this trait?
Scotland has the highest percentage of redheads in the world at 13%. Assuming Hardy Weinberg equilibrium, calculate the frequency of p and q.