1. Incomplete dominance

2. Incomplete Dominance No dominant or recessive traits Traits are of equal value All capital letters are used Exponents or apostrophes are used to signify the presence of genes Three variations are possible

3. Examples: Snapdragons True-breeding red = R 1 R 1 True-breeding white = R 2 R 2 Offspring are pink = R 1 R 2

4. Snapdragon Phenotypes

5. Sickle Cell Anemia Genetic disorder causing the red blood cells to be incorrectly shaped Normal shape – disc shaped – round with sunken center Abnormal shape – crescent or sickle shaped A’A

6. Sickle Cell Anemia

7. Possibilities AA Normal shaped Red Blood Cell A’A Trait carrier A’A’ Sickle Cell Anemia

8. Red Blood Cells Video

9. Function of Red Blood Cells Normally carries oxygen to cells and exchanges for carbon dioxide Misshapen cells can not carry the needed oxygen Misshaped cells also get stuck in capillaries causing mini blood clots and lack of oxygen to cells

10. Who is most often affected? In the U.S. 70,000 people are affected One in every 400 African-American newborns has SCA One in every 10 African Americans has the trait Sicilians May also be in all ethnic groups

11. Identification? Blood test after birth

12. Complications Pain/Cramps Sharp and shooting in arms and legs Strokes/Blood clots Most common in children under 10 Overt stroke before completing high school causing physical impairment Silent strokes do no cause outward symptoms but cause difficulty in learning Fatigue/Lack of oxygen