1. Non Mendelian Traits (Mendelian Exceptions)

2. Incomplete Dominance
A cross between organisms with two different phenotypes
Ex: Red (RR) x White (WW)
Produce offspring with a third phenotype that is a blending of the parental traits
- Ex: Pink (RW)
red
pink
white

3. Incomplete Dominance
EX: If a homozygous red flowered snap dragon plant (RR) is crossed with a homozygous white flowered snap dragon plant (WW), all of the offspring will have pink flowers.
RED flower x WHITE flower  PINK flower RW RW RW RW

4. Incomplete Dominance RR BB RB
In another flower, if red ____ and blue ____ flowers are crossed, they produce a 3rd purple ____ flower
- What would be the genotype ratio and phenotype ratio if you crossed two purple flowers? BB RB

5. Incomplete Dominance Cross of two purple flowers ____ X ____
What are gamete possibilities? RB X RB
genotype ratio
1RR : 2RB : 1BB
phenotype ratio
1red : 2 purple : 1 blue
Can you have a heterozygous red or hybrid blue flower? ___ RB RB R B RR RB R
red
purple BB RB B
purple
blue no

6. In Labrador retrievers, yellow is incompletely dominant to black
In Labrador retrievers, yellow is incompletely dominant to black. The heterozygous phenotype is chocolate. Cross a yellow lab with a chocolate lab.
- Find gametes
- Find genotype percent
- Find phenotype percent

7. Codominance A cross between organisms with two different phenotypes
- Ex: Red x White
Produce offspring with a third phenotype that displays BOTH traits at the same time
- Ex: Red and White Striped

8. Codominance
EX: If a homozygous red flowered snap dragon plant (RR) is crossed with a homozygous white flowered snap dragon plant (WW), all of the offspring will have Red and white flowers.
- RED flower x WHITE flower  RED & WHITE flower

9. Codominance Andalusian chickens show patterns of codominance.
If you cross a black (BB) chicken with a white (WW) chicken
You get a black & white speckled (BW) chicken

10. Human Codominance Sickle-Cell Anemia
An individual who is heterozygous for sickle-cell alleles will express BOTH normal and abnormal shaped blood cells
The oxygen carrying protein hemoglobin differs by one amino acid this causes regular disk shape to be changed to abnormal half moon or sickle shaped.
Abnormally shaped blood cells slow blood flow, block vessels, and result in tissue damage and pain.
Heterozygous individuals are said to have the sickle-cell trait because they show signs of sickle-cell related disorders if the availability of oxygen is reduced.
Normal red blood cell
Sickle cell

11. Human Codominance Blood Types
Blood type is determined by multiple alleles. This means there are more than two types of alleles possible that can make up a paring.
Allele A: red blood cells produce A antigens (protein) on the outside of the cell
Allele is expressed IA or A because it is dominant
Allele B: red blood cells produce B antigens (protein) on the outside of the cell
Allele is expressed IB or B because it is dominant
Allele O: red blood cells will NOT produce an antigen (protein)
Allele is expressed I or O because it is recessive

12. Human Codominance Blood Types
Determining Blood types is necessary before you receive a blood transfusion because incompatible red blood cells clump together or clot causing death.
Your immune system or antibodies recognizes the red blood cells belonging to you. If cells with a different type of antigen enter your body your immune system will attack them

13. Multiple Alleles
______ different phenotype blood groups: A, B, O, & AB
Are produced by ______ different alleles: A, B, and O
FILL in your chart & answer the
following questions
Which ones are homozygous?
Which ones are heterozygous?
Which one is codominance?
Four
Phenotype
All Genotypes Possible
Type A (Dominant)
IAIA (AA), IAi (AO)
Type B (Dominant)
IBIB (BB), IBi (BO)
Type AB (Codominant)
IAIB (AB)
Type O
(recessive)
ii (OO)
three

14. Will the following cause death?
Can a person with type A blood receive type O blood?
Can a person with type B blood receive type AB blood?

15. Multiple Alleles
Example problems: Blood type crosses