1. Sickle Cell Anemia

3. Incomplete Dominance

6. Sex linked traits

7. Multiple Alleles
All chicken have combs on their heads, but it does not always look the same. The comb is a fleshy growth on the top of the chicken's head. Both male and female chickens have combs, but the ones on the male are larger. Combs of different breeds may look different in shape and even in color.
Chicken comb features:
rrpp = single
rrP_ = pea
R_pp = rose
R_P_ = walnut
1. What must be the genotypes of the two parents for the outcome to always be a walnut offspring?
 (neither can be walnut to begin with) ____________ x _____________ = walnut (R_P_)
2. Show a Punnett square for the following cross and describe the phenotypic ratios. RrPp x RrPp
3. Show a punnett square for the following cross and describe the phenotypic ratios. rrpp x RrPp
4. Show a punnett square for the following cross and describe the phenotypic ratios. rrpp x rrPp
5. A rose crossed with a pea produces six walnut and five rose offspring. What must be the genotypes of the parents? Show the cross.

8. Hardy-Weinberg Principle
Natural selection acts on individuals, but only populations evolve
Explain this statement

9. Hardy-Weinberg Principle
Describes a non-evolving population
The gene pool does not change
Gene pool - all alleles for all loci in the population
Allele frequencies remain constant in non-evolving populations
Why do this?
Allelic variation within a population can be modeled by the Hardy-
Weinberg equations.

10. A Population in Hardy-Weinberg Equilibrium http://zoology. okstate
The seven assumptions underlying Hardy–Weinberg equilibrium are as follows:
organisms are diploid
only sexual reproduction occurs
generations are non overlapping
mating is random
population size is infinitely large
allele frequencies are equal in the sexes
there is no migration, mutation or selection
Fig. 23-6

11. Interpretation:
A population with 80% dominant and 20% recessive alleles
that meets the conditions for Hardy-Weinberg equilibrium
will pass 80% dominant and 20% recessive alleles to the next generation
Alleles in the population
Frequencies of alleles
Gametes produced
p = frequency of
Each egg:
Each sperm:
CR allele = 0.8
q = frequency of
80%
chance
20%
chance
80%
chance
20%
chance
CW allele = 0.2

12. Hardy-Weinberg equations:
p + q = 1
p2 + 2pq + q2 = 1
Describes alleles in a gene pool
This is the equation for a trait with 2 alleles
Can be used to predict genotypes
p – represents dominant allele
q – represents the recessive allele
Worksheet 3, 4 and 5

13. 80% CR ( p = 0.8) 20% CW (q = 0.2) Sperm CR (80%) Eggs CW (20%) CR CW
Worksheet: #6
Sperm CR
(80%) CW
(20%) CR
(80%)
Figure 23.7 The Hardy-Weinberg principle
Eggs
64% ( p2)
CRCR
16% ( pq)
CRCW
4% (q2)
CW CW
16% (qp)
CRCW CW
(20%)

14. Gametes of this generation:
64% CRCR, 32% CRCW, and 4% CWCW
Gametes of this generation:
64% CR   +    16% CR    =   80% CR = 0.8 = p
4% CW     +    16% CW   =   20% CW = 0.2 = q
Genotypes in the next generation:
Figure 23.7 The Hardy-Weinberg principle
64% CRCR, 32% CRCW, and 4% CWCW plants

15. Reality Hardy-Weinberg - hypothetical population
In real populations, allele and genotype frequencies change over time

16. 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: 
A. What is the frequency of the "aa" genotype in the population? 
B. What is the allele frequency of the "a" allele? 
C. What is the frequency of the "A" allele in the population? 
D. What is the frequencies of the genotype "Aa” in the population? 
E. What is the frequencies of the two possible phenotypes if "A" is completely dominant over "a."
The winged trait is
dominant.