1. Patterns of Heredity & Human Genetics
Chapter 12
Patterns of Heredity & Human Genetics

2. Pedigrees

4. Simple Recessive Heredity
Most disorders are caused by recessive alleles
Cystic fibrosis
Tay-sachs disease
Phenylketonuria

6. Simple Dominant Heredity
Only one dominant gene causes the trait to appear
Huntington’s disease

8. Incomplete Dominance Heterozygous individual shows a third trait
A blending of the dominant and recessive

9. Codominance Heterozygous individual shows both traits at the same time
Blood type, sickle cell anemia

10. Sex Determination Humans have 46 chromosomes 22 pairs of autosomes
1 pair of sex chromosomes
XX is female
XY is male

11. Sex-linked Disorders Usually more common in males than females
Colorblindness
Hemophilia

13. Sickle Cell Anemia Created through mutation of a single base pair
Disease of the red blood cells
Found mainly in people of African ancestry

15. Multiple Alleles Characteristic controlled by more than two alleles
Results in more than two possible outcomes
Skin color, eye color, height

16. Karyotype

17. Down Syndrome

18. Turner Syndrome

19. Klinefelter Syndrome

20. Blood Types Controlled by three genes: IA, IB, i
Two genes are codominant
One gene is recessive
Results in 4 blood types: A, B, AB,O