1. Incomplete Dominance Neither allele is fully dominant over the other, but combine and display a new phenotype that is a blending of the two alleles EX: Flower color in Snapdragons C R C R = red C W C W = white C R C W = pink

2. Problem: Incomplete Dominance Show the cross between a pink and a white flower. - C R C R (2); C R C W (2) - ratio 1:1 - pink (2); white (2) - ratio 1:1 C R C W CWCWCWCW CWCWCWCW CWCWCWCW CRCWCRCW GENOTYPES: PHENOTYPES: CRCWCRCW

3. Codominance Both alleles are fully dominant and are expressed equally in the heterozygous condition EX: Roan Cows

4. Codominance EX: Sickle Cell Anemia in humans NN = normal cells SS = sickle cells NS = some of each

5. Problem: Codominance Show the cross between an individual with sickle-cell anemia (S) and another who is a carrier but not sick (N). N S SSSS - NS (2) SS (2) - ratio 1:1 - carrier (2); sick (2) - ratio 1:1 GENOTYPES: PHENOTYPES: NS SS

6. Let’s Stop and Think… Let’s say there are two alleles for the hair color trait- red and blue – What would be the resulting phenotype of a heterozygous pair if the alleles showed incomplete dominance? A. Red B. Blue C. Purple D. Red and Blue patches

7. Let’s Stop and Think…  Let’s say there are two alleles for the hair color trait- red and blue  What would be the resulting phenotype of a heterozygous pair if the alleles showed codominance?  A. Red  B. Blue  C. Purple  D. Red and Blue patches  Let’s say there are two alleles for the hair color trait- red and blue  What would be the resulting phenotype of a heterozygous pair if the alleles showed codominance?  A. Red  B. Blue  C. Purple  D. Red and Blue patches