1. Incomplete Dominance Vivian R. Smith E. B. Aycock Middle School

2. Incomplete Dominance A form of intermediate inheritance in which heterozygous alleles are both expressed, resulting in a combined phenotype.

3. An incomplete dominance example, both the instructions for “make red” and the instructions for “make white” are carried out. The result is PINK.

4. Example A RED Four-o-Clock flower and a WHITE Four- O-Clock flower are cross pollinated. What are the possible offsprings?

5. RR X WW Red Four-O-Clock White Four-O-Clock

6. RR W W RW Genotypes Red RR White WW Pink RW

7. 100% of the offspring Pink Four-O-Clock flower

8. Sickle Cell Example

9. Red Blood Cells Normal Cells Disc shaped Soft and jelly like Can move easily through the blood vessels Lasts 120 days Sickle Cells Sickle-shaped Hard Can not easily move through blood vessels. Clogs the vessels and can stop blood flow. Lasts 60 days, which causes a lack of hemoglobin and oxygen Affects mainly people of African, Mediterranean, India, Middle East decent

10. Blood Cells and Genetics Normal Cells: NN –Normal cells, disc shaped Sickle Cell Trait: NS –Carries the gene for sickle cell but does not show signs Sickle Cell Disease: SS –Has Sickle Cell Anemia and suffers from complications

11. Example 1 NN S S NS Do the offsprings have Sickle Cell Disease?

12. Example 2 NS N S NN NS SS What percentage of the offsprings have Sickle Cell Disease?

13. Resources Red Four-O-Clock http://www.dkimages.com/discover/previews/927/703437.JPG http://www.dkimages.com/discover/previews/927/703437.JPG White Four-O-Clock http://www.fireflyforest.com/flowers/whites/white75.html http://www.fireflyforest.com/flowers/whites/white75.html Pink Four-O-Clock http://davie.tv/DavTV/images/2006/4oClock.JPG http://davie.tv/DavTV/images/2006/4oClock.JPG Sickle Cell http://www.thirdage.com/healthgate/Images/si55551158.jpg http://www.thirdage.com/healthgate/Images/si55551158.jpg http://www.defiers.com/scd.html