1. Types of Inheritances III
Pp 237,

2. Multigene Traits
More than one gene is responsible for a trait (phenotype)

3. Epistasis

4. Epistasis One gene affects the outcome of the other gene
Ex: Labrador Retriever's coats are controlled by two genes: E and B.
- E gene: if pigment is present or absent
- B gene: how much pigment is present

5. Polygenic traits

7. Polygenic traits
These traits are continuous and many genes are responsible for producing one trait
Actual number is unknown but it is hypothesized that up to 16 genes are responsible for eye color

9. Environmental

10. Environmental
Environment such as soil pH can influence the expression of a gene

11. Ex: More testosterone = more baldness
Sex-influenced trait
Similar to environmental influenced trait but think of the human body as an internal environment
Controlled by autosomes, but influenced by sex hormones
Specific hormones influence trait/genotype
Ex: More testosterone = more baldness

13. Scientists Have Observed Epigenetic Memories Being Passed Down For 14 Generations

14. Epigenetics
The study of changes in an organism’s phenotype without a change in genotype
Environmental exposures can change the way your DNA works (without changing the DNA itself) and passed on to your offspring.
Changes have to occur in the gametes (not body cells)

15. What type of inheritance determines skin color?