1. Sex-Linked Traits

2. Traits whose alleles are located on sex chromosomes X-linked X X-linked traits are traits whose allele is carried on the X chromosome Y-linked Y Y-linked traits are traits whose allele is carried on the Y chromosome. Most Y-linked mutations lead to sterility, and can not be inherited.

3. Sex-linked = X-linked Because X-linked traits are traits the predominant sex-linked traits, for our purposes:

4. Color Blindness: An X-linked Recessive trait

5. Punnett Square XCXC XCXC XcXc Y Carrier mother Unaffected father XCXcXCXc XCXcXCXc XCYXCYXcYXcY 25% Colorblind male

6. A Pedigree - Colorblindness

7. Hemophilia: Another X-linked Recessive trait

8. Punnett Square XHXH XHXH XhXh Y Carrier mother Unaffected father XHXHXHXH XHXhXHXh XHYXHYXhYXhY 25% Hemophiliac male

9. Hemophilia in Europe’s Royalty