1. Non Mendelian Inheritance Exceptions to the rule

2. Intermediate Inheritance When the heterozygous offspring have a trait that isn’t exactly the trait of either purebred parent When the heterozygous offspring have a trait that isn’t exactly the trait of either purebred parent

3. Incomplete Dominance Sometimes a cross between two individuals with two different phenotypes can result in offspring with a third phenotype that is a blend of the parents’ phenotypes Sometimes a cross between two individuals with two different phenotypes can result in offspring with a third phenotype that is a blend of the parents’ phenotypes

4. Example of incomplete dominance: Snapdragons

5. Codominance In Codominance, the "recessive" & "dominant" traits appear together in the phenotype of hybrid organisms. red x white ---> red & white spotted

6. Example of codominance: Color of cornsnakes

7. Cornsnakes

8. Example of codominance: Roan Cowsand Horses Red x White  Red and White Spotted Red x White  Red and White Spotted

9. Polygenic Trait A single trait that is affected by more than one gene A single trait that is affected by more than one gene Each gene may be inherited independently Each gene may be inherited independently What do you think that results in? What do you think that results in?

10. Example of a polygenic trait Eye color Eye color There are genes for There are genes for Tone of pigment (what color it is) Tone of pigment (what color it is) The amount of pigment The amount of pigment Position of pigments (look at people’s eyes- there are many different patterns in the iris) Position of pigments (look at people’s eyes- there are many different patterns in the iris)

11. Eye color continued

12. Multiple Alleles Many genes have more than just two alleles (forms of the gene) Many genes have more than just two alleles (forms of the gene) If there are three or more alleles for a trait, it is called multiple alleles If there are three or more alleles for a trait, it is called multiple alleles

13. Example of multiple alleles: Human Blood Type

14. Pleiotropy When a single gene affects more than one trait When a single gene affects more than one trait

15. Example of Pleiotropy: White Cats The first effect is the white fur color The first effect is the white fur color The second effect is that the cats are often deaf in one or both ears The second effect is that the cats are often deaf in one or both ears

16. Example of Pleiotropy: Cystic Fibrosis

17. Environmental Effects The environment can influence the expression of genes The environment can influence the expression of genes

18. Example of effect of temperature Ptarmigan in the tundra- change color depending on the temperature and weather Ptarmigan in the tundra- change color depending on the temperature and weather

19. Soil acidity and hydrangea

20. Social Conditions Sex changing Japanese gobies Sex changing Japanese gobies

21. What else??? Can you think of another factor that could affect the expression of certain genes? Can you think of another factor that could affect the expression of certain genes?