1. Human Genetics

2. Sex Chromosomes
XX = girl XY= boy

3. Sex-linked Traits traits on the sex chromosomes
X chromosome has about: 1000 genes
Y has about: 26 genes

4. Sex-Linked Traits
Most debilitating (harmful) sex-linked traits are recessive
Females must get 2 alleles on both X chromosomes to get these diseases
If males get 1 allele on their X chromosome then they get the disease

5. Examples of Sex-Linked Genetic Diseases
Hemophilia :1 or more blood clotting factors not produced
People can’t stop bleeding

6. Muscular Dystrophy
a muscle disorder that results in weakening and loss of skeletal muscles

7. Male Pattern Baldness

8. Red-Green Color Blindness
Individual can’t see red and green colors
Found in 1 in 10 males and 1 in 100 females
in the U.S.

9. Tests for Red-Green Colorblindness

10. What numbers are in the circles?

11. Example Problem Cross a normal female with a color blind male
How many of their daughters will be color blind? What about their sons?

12. Cross a color-blind male with a carrier female.
Will any of their sons be color-blind? Any of their daughters?

13. Cross a normal male with a carrier female
Cross a normal male with a carrier female. What kind of children will they have?