1. Unit 6 Notes: Non-Mendelian
Genetics
(1)

2. (1) Non-Mendelian? Mendelian …. Non-Mendelian…
There’s dominant and recessive.
You either look like the dominant or recessive trait.
Non-Mendelian…
There’s a mixture of dominant AND recessive.
There’s more than one trait affecting the phenotype.

3. (2) Types of NM Genetics:
Incomplete Dominance
Codominance
Sex-Linked
Polygenic Traits
Multiple Alleles

4. (3) Incomplete Dominance:
One allele is not completely dominant over the recessive allele.
Result = Looks like a blending of traits.
The recessive trait is partially expressed in combination with the fully expressed dominant trait.
Genotype Examples:
AA = Black
BB = White
AB = Gray Appearance

7. A Red (RR) Snap-Dragon Flower is crossed with a White (WW) Flower .
(4) Incomplete Dominance EXAMPLE:
A Red (RR) Snap-Dragon Flower is crossed with a White (WW) Flower .

8. (5) Codominance:
2 or more alleles are equally dominant, no recessive/hidden allele.
Result = Both traits are fully expressed at the same time.
Not a blending, Not a partial expression.
Looks like spotting.
Genotype Examples:
AA = Black
BB = White
AB = Black and White striped

11. (6) Codominance EXAMPLE:
Chickens can be Homozygous Black (BB), Homozygous White (WW), or Erminette (BW) having black and white feathers. Cross a Erminette Chicken with a Black Chicken.

12. (7) Sex-Linked: Xh Y = Male with Disorder / Disease
The alleles are only located on the sex-chromosomes (X or Y).
Result = Individuals can be normal, carriers, or have a disease/disorder.
Genotype Examples:
XH XH = Normal Female
XH Xh = Female Carrier
Xh Xh = Female with Disorder / Disease
XH Y = Normal Male
Xh Y = Male with Disorder / Disease

14. (8) Sex-Linked EXAMPLE:
In humans, hemophilia is an X-linked recessive trait. A Female Carrier and a Normal Male have children…

15. (9) Polygenic Traits:
Physical features which are created by the expression of more than one gene.
Examples:
Eye Color
Hair Color
Skin Color
Height
Weight

17. (10) Multiple Alleles:
A single gene which has more than 2 allele variations.
Example: Blood Type
Tags on Blood Cells… A , B , Rh , No Tag
Blood Types… A , B , O , AB A+ , B+ , O+ , AB+