1. BIOZONE: 238-251 due Wed 11/05 BIOZONE: 238-251 due Wed11/05
Sponge: Set up Cornell Notes on pg. 55
Topic: 5.4 Evolution: Hardy-Weinberg Principle
Essential Question: Is the Hardy-Weinberg principle a realistic model to use to study evolution?
BIOZONE: due Wed 11/05
5.4 Evolution: Hardy-Weinberg Principle
Is the Hardy-Weinberg principle a realistic model to use to study evolution?
Key Vocabulary:
Hardy-Weinberg Principle
BIOZONE: due Wed11/05

2. The Hardy-Weinberg Principle
Hardy-Weinberg Principle: is used to predict genotype frequencies in a population
States that allelic frequencies will remain the same from generation to generation assuming five conditions are met (below)
Describes populations that are NOT evolving
This principle is important because it gives biologists a standard from which to measure changes in allele frequency in a population.

3. The Hardy-Weinberg Principle
Allele frequencies will remain the same from generation to generation assuming five conditions are met:
Very large population: no genetic drift.
In each generation, some individuals may, just by chance, leave behind a few more descendants (and genes, of course!) than other individuals. The genes of the next generation will be the genes of the “lucky” individuals, not necessarily the healthier or “better” individuals.
2. No emigration or immigration: no gene flow. No organisms coming or going into the population.

4. The Hardy-Weinberg Principle
3. No mutations: No new alleles added to gene pool.
4. Random mating: No sexual selection. They will mate with any female/male.
5. No natural selection: All traits aid equally in survival. No traits are better than others.
Real populations rarely meet all five conditions!!!

5. The Hardy-Weinberg Equation
In order to calculate the frequencies of alleles, genotypes, or phenotypes within a population the Hardy-Weinberg equation is needed
Useful in determining how fast a population is changing or in predicting the outcomes of matings or crosses
Values predicted by the equation are those that would be present if the population is in equilibrium.
The Hardy-Weinberg equation is based on Mendelian genetics. It is derived from a simple Punnett square in which p is the frequency of the dominant allele and q is the frequency of the recessive allele.

6. The Hardy-Weinberg Equation
2 (pxq)

7. The Hardy-Weinberg Example
BB(p²)= 36% of population is homozygous dominant Bb (2pq)= 48% of population is heterozygous Bb (q²)= 16% of population is homozygous recessive Freq of B allele? Freq of b allele?

8. p + q = 1 How can I find p if I know p²? Use the square root!
How to find allele frequencies:
p + q = 1
p= dominant allele frequency
q= recessive allele frequency
How can I find p if I know p²?
Use the square root!
√ of p² = p

9. How to find allele frequencies:
p + q = 1
p= the frequency of the dominant allele (B) (p+ ½ 2pq)
q= frequency of the recessive allele (b) (q+ ½ 2pq)
Must add up to 1
p= =.60
q= =.40
= 1

10. The Hardy-Weinberg Principle Practice
Albinism  is a rare genetically inherited trait that is only expressed in the phenotype of homozygous recessive individuals (aa).  The most characteristic symptom is a marked deficiency in the skin and hair pigment melanin.  This condition can occur among any human group as well as among other animal species.  The average human frequency of albinism in North America is only about 1 in 20,000.
Referring back to the Hardy-Weinberg equation (p² + 2pq + q² = 1), the frequency of homozygous recessive individuals (aa) in a population is q². 
Therefore, in North America the following must be true for albinism: q² = 1/20,000 =
Figure out the predicted frequency of homozygous individuals, heterozygous individuals, and homozygous recessive individuals. (HINT: Find the square root of q² to find q.)

11. Referring back to the Hardy-Weinberg equation (p² + 2pq + q² = 1), the frequency of homozygous recessive individuals (aa) in a population is q². 
Therefore, in North America the following must be true for albinism: q² = 1/20,000 =
Figure out the predicted frequency of homozygous individuals, heterozygous individuals, and homozygous recessive individuals. (HINT: Find the square root of p2 to find p.)
p² + 2pq
Sq. root of = q= .007
p + q= p = 1
1-.007= p p= .993
= 1

12. Referring back to the Hardy-Weinberg equation (p² + 2pq + q² = 1), the frequency of homozygous recessive individuals (aa) in a population is q². 
Therefore, in North America the following must be true for albinism: q² = 1/20,000 =
Figure out the predicted frequency of homozygous individuals, heterozygous individuals, and homozygous recessive individuals. (HINT: Find the square root of p2 to find p.)
p2 + 2pq
Sq root of = q= .007
p + q= p = 1
1-.007= p p= .993
= 1
Now let’s input this information into the Hardy-Weinberg equation: (p² + 2pq + q² = 1)
p²=
2pq=
q²=

13. Change to %s to find the frequency for each in the population
Referring back to the Hardy-Weinberg equation (p² + 2pq + q² = 1), the frequency of homozygous recessive individuals (aa) in a population is q². 
Therefore, in North America the following must be true for albinism: q² = 1/20,000 =
Figure out the predicted frequency of homozygous individuals, heterozygous individuals, and homozygous recessive individuals. (HINT: Find the square root of p2 to find p.)
p2 + 2pq
Sq root of = q= .007
p + q= p = 1
1-.007= p p= .993
= 1
Now let’s input this information into the Hardy-Weinberg equation: (p² + 2pq + q² = 1)
p²= .986
2pq= .014
q²=
Change to %s to find the frequency for each in the population

14. p²= predicted freq. of homozygous dominant individuals= .986….98.6%
2pq= predicted freq. of heterozygous individuals= .014…..1.4 %
q²= predicted freq. of homozygous recessive individuals= …..005%
With a frequency of .005% (about 1 in 20,000), albinos are extremely rare. 
However, heterozygous carriers for this trait, with a predicted frequency of 1.4% (about 1 in 72), are far more common than most people imagine. 
There are roughly 278 times more carriers than albinos. 
Clearly, though, the vast majority of humans (98.6%) probably are homozygous dominant and do not have the albinism allele.

15. The Hardy-Weinberg Principle Practice
You have sampled a population in which you know that the percentage of the homozygous recessive genotype (aa) is 36%. Using that 36%, calculate the following:
1. The frequency of the "aa" genotype.
2. The frequency of the "a" allele.
3. The frequency of the "A" allele.
4. The frequencies of the genotypes "AA" and "Aa."
5. The frequencies of the two possible phenotypes if "A" is completely dominant over "a."
Find:
q²= q= p=
p²=
2pq=

16. The Hardy-Weinberg Principle Practice
You have sampled a population in which you know that the percentage of the homozygous recessive genotype (aa) is 36%. Using that 36%, calculate the following:
aa= 36… q²= .36
Sq. Root of .36= .6
q = .6
p + q = 1
_____ + .6= 1
p= .4
Now let’s input this information into the Hardy-Weinberg equation: (p² + 2pq + q² = 1)
Change to %s

17. The Hardy-Weinberg Principle Practice
You have sampled a population in which you know that the percentage of the homozygous recessive genotype (aa) is 36%. Using that 36%, calculate the following:
p² + 2pq + q² = 1
(.4)² + 2(.4x.6) + (.6)² = 1
= 1
AA= 16%
Aa= 48%
aa= 36%
Now let’s input this information into the Hardy-Weinberg equation: (p² + 2pq + q² = 1)
Change to %s

18. The Hardy-Weinberg Principle Practice
You have sampled a population in which you know that the percentage of the homozygous recessive genotype (aa) is 36%. Using that 36%, calculate the following:
The frequency of the "aa" genotype.
36%

19. The Hardy-Weinberg Principle Practice
You have sampled a population in which you know that the percentage of the homozygous recessive genotype (aa) is 36%. Using that 36%, calculate the following:
2. The frequency of the "a" allele.
(1/2 of 2pq)= .6 or 60%

20. The Hardy-Weinberg Principle Practice
You have sampled a population in which you know that the percentage of the homozygous recessive genotype (aa) is 36%. Using that 36%, calculate the following:
3. The frequency of the "A" allele.
(1/2 of 2pq) = .4 or 40%

21. The Hardy-Weinberg Principle Practice
You have sampled a population in which you know that the percentage of the homozygous recessive genotype (aa) is 36%. Using that 36%, calculate the following:
4. The frequencies of the genotypes "AA" and "Aa”.
AA= 16%
Aa= 48%

22. The Hardy-Weinberg Principle Practice
You have sampled a population in which you know that the percentage of the homozygous recessive genotype (aa) is 36%. Using that 36%, calculate the following:
5. The frequencies of the two possible phenotypes if "A" is completely dominant over "a.“
48+ 16= 64% of the population will show the trait.
36% will be recessive for the trait.

23. The Hardy-Weinberg Principle Practice
Please complete the Hardy-Weinberg practice problems (both sides)

24. The Hardy-Weinberg Principle Pre-Lab
Solve.
Fill out table
Genotype
Frequency of allele pairs in population
Gene frequency (Freq. #/Total)
Homozygous Dominant LL p²
Heterozygous Ll
2pq
Homozygous Recessive ll q²
Total
Find:
q²= q= p=
p²=
2pq=

25. The Hardy Har Har-Weinberg Principle Lab
Read your Hardy-Weinberg Principle notes for background
Write hypothesis. What do you think is going to happen to the allele frequencies as we move from generation to generation?

26. P 1 (Parental Generation) P1
Homozygous Dominant (LL)
Heterozygous
(Ll)
Homozygous Recessive (ll) 8 16 8
Calculate gene frequencies for each.
.25
.50

27. P 1 (Parental Generation) P2
Homozygous Dominant (LL)
Heterozygous
(Ll)
Homozygous Recessive (ll) 9 18 9
Calculate gene frequencies for each.
.25
.50

28. Homozygous Dominant (LL) Homozygous Recessive (ll)
F1 (Generation 1)
Homozygous Dominant (LL)
Heterozygous
(Ll)
Homozygous Recessive (ll)
Calculate gene frequencies for each.

29. Homozygous Dominant (LL) Homozygous Recessive (ll)
F2 (Generation 2)
Homozygous Dominant (LL)
Heterozygous
(Ll)
Homozygous Recessive (ll)
Calculate gene frequencies for each.

30. Homozygous Dominant (LL) Homozygous Recessive (ll)
F3 (Generation 3)
Homozygous Dominant (LL)
Heterozygous
(Ll)
Homozygous Recessive (ll)
Calculate gene frequencies for each.

31. Homozygous Dominant (LL) Homozygous Recessive (ll)
F4 (Generation 4)
Homozygous Dominant (LL)
Heterozygous
(Ll)
Homozygous Recessive (ll)
Calculate gene frequencies for each.

32. Homozygous Dominant (LL) Homozygous Recessive (ll)
F5 (Generation 5)
Homozygous Dominant (LL)
Heterozygous
(Ll)
Homozygous Recessive (ll)
Calculate gene frequencies for each.

33. The Hardy Har Har-Weinberg Principle Lab
Please answer the 7 analysis questions on a separate piece of paper
Staple to lab notes/data sheet

34. The Hardy-Weinberg Principle Lab Report
Hypothesis
Data collection
1-2 data tables
Data Processing/Analysis
1-2 Graphs
Conclusion
Only part I