1. Foothill High School Science Department Introduction To Genetics Incomplete Dominance, Codominance, Polygenic Traits & Multiple Alleles

2. Foothill High School Science Department Beyond Dominant & Recessive Alleles Key Concept Key Concept: Some Alleles Are Neither Dominant Nor Recessive, Plus Many Traits Are Controlled By Multiple Alleles or Multiple Genes.

3. Foothill High School Science Department Incomplete Dominance Incomplete Dominance The Heterozygous Phenotype Is Between The Homozygous Phenotypes. ( Both Alleles Expressed In One Cell)

4. Foothill High School Science Department

5. Codominance Both Alleles Completely Expressed Red Hair Cattle Crossed With White Haired Cattle Produce Roan (Pink Brown) Cattle That Have Both Colored Hairs. (Both Alleles Expressed Independently. There are no pink hairs, each hair is either Red or White.) (Both Alleles Expressed Independently. There are no pink hairs, each hair is either Red or White.) ( Only One Allele Is Expressed In Each Cell, BUT Different Cells Express Different Alleles)

6. Foothill High School Science Department Codominance REDWHITE ROAN

7. Foothill High School Science Department Multiple Alleles A Gene Is Controlled By >2 Alleles. – Individuals Can Only Have 2 Alleles – Populations Can Have More Than Two Rabbit Fur Color Blood Types Eye Color

8. Foothill High School Science Department Human Blood Groups – ABO I A & I B Codominant I A & I B Codominant i Recessive (Type O gene) i Recessive (Type O gene) – Rh ( Rhesus Monkey ) Rh+ Dominant Rh+ Dominant Rh- Recessive Rh- Recessive

9. Foothill High School Science Department Codominance – ABO Blood Type

10. Foothill High School Science Department Codominance &Multiple Alleles

11. Foothill High School Science Department Multiple Alleles

12. Foothill High School Science Department Polygenic Traits Phenotypes Produced By The Interaction Of Several Genes. – Human Skin Color – Human Skin Color Is Controlled By More Than 4 Different Genes. – Eye Color – Eye Color is Controlled By At Least 3 Genes

13. Foothill High School Science Department Polygenic & Multiple Alleles