Hardy Weinberg
Joy Killough
Westwood High School
Austin, TX
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.
This is
more like
spawning
Let’s Reproduce...
Meiosis Anyone?
Then into the gene
pool
What is our new
allele frequency?
1. Natural Selection
2. Calculate survivor allele frequency
3. SURVIVORS only...Reproduce
4. 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?
•p
2
+ 2pq + q2 = 1
Hardy-Weinberg describes the status quo and
provides a way to describe change.
5 conditions must be met:
Allele frequencies won’t change if…
1. The population is large
2. Mating is random
3. There is no mutation
4. No immigration or emigration
5. There is no selection
19
All the alleles in a population must
equal 100%
Say A and a are the alleles at a locus
Diploid organisms have 2 loci
p = the frequency of A
q = the frequency of a
So the frequency of p + q must equal 100%
or 1.0
20
Frequency of possible combinations of p
and q for diploid organisms
• (p+q) (p+q) =
2
p
+ 2pq +
2
q
21
• 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.