1. Complex Inheritance of Human Traits

2. Codominance in Humans
Phenotypes of both homozygotes are produced in the heterozygote
Recall the checkered rooster
Sickle-cell anemia

3. Sickle-cell Anemia Disorder where red blood cells are sickle shaped
Normally concave
Shorter life span and can slow bloodflow or block small vessels
1 in 12 African Americans is heterozygous for the disorder

5. Malaria Sickle Cell

6. Multiple Alleles in Humans
Blood types
Can be A, B, AB, or O

7. Type A The IA allele is dominant to i
IAi or IAIA will give you type A blood
Surface protein A is produced

8. Type B The IB allele is also dominant to i
IBIB or IBi will =type B blood
Surface protein B is produced.

9. Type AB The IA and IB alleles are codominant to each other
IAIB you will have type AB blood
Will produce both surface proteins

10. Type O The i allele is recessive Produces no surface molecule
Homozygous ii you have blood type O

12. Sex-Linked Traits in Humans
Traits that are determined by genes that are carried on the sex chromosomes
Most of these genes are located on the X chromosome

14. Red-green Color Blindness
People who have red-green color blindness can't differentiate these two colors

16. Hemophilia: An X-linked disorder
Blood fails to clot normally because of a deficiency or abnormality of one of the clotting factors
1 male in every has hemophilia but only about one in 100 million females
Why?

17. Polygenic Inheritance in Humans
These kinds of traits usually represent a range of variation that is measurable
Color variations in human eyes
Skin color

19. Changes in Chromosome Numbers
Unusual numbers of autosomes
Down syndrome: Trisomy 21
Unusual numbers of sex chromosomes
Turner’s Syndrome and Klinefelter's Syndrome