1. No Bell Work today! Set up the next page in your journal… Page: 46 Date: 12-10-15 Title: Genetics – Sex-linked Essential Question: How can I predict genetic outcomes of non-Mendelian traits?

2. What do you think a “sex-linked” trait is? Examples?

3. Remember! Everyone inherits an X chromosome from mom and either an X (girls) or a Y (boys) from dad.

4. Sex-linked traits: determined by genes carried on either the X or Y chromosome If they are carried on the X-chromosome they are referred to as “X-linked” If they are carried on the Y chromosome they are referred to as “Y-linked” Y-linked disorders are very rare and often cause infertility in men

5. X-linked dominant Any affected chromosome will cause the trait to appear These conditions (such as vitamin D resistant rickets) are rare and can affect both men and women Men are more affected than women Both men and women can pass on the affected chromosome to their children

6. 2. Rickets is an x-linked dominant trait. What would be the phenotypic outcome if a normal woman and a man with rickets had children? XRXR Y X X XRXXRX XY XRXXRX X R = rickets X = normal DAD = X R Y MOM = XX Their daughters would have rickets and their sons would not

7. In 18 words summarize these two diagrams.

8. X-linked recessive Women must have two affected chromosomes to show the trait; men with an affected X will show the trait These disorders (such as hemophilia and color blindness) more frequently affect men than women GenotypePhenotype XYMan who can see all colors XCYXCYColorblind man XXWoman who can see all colors XCXXCXWoman who can see all colors (carrier) XCXCXCXC Colorblind woman

9. 3. Colorblindness is an X-linked recessive trait. What would be the expected outcome if a carrier woman (X C X) and a normal man had children? X Y XCXC X XCXXCX XCYXCY XX XY X C = colorblind X= normal DAD = XY MOM = X C X DAUGHTERS: 50% carrier, 50% normal SONS: 50% colorblind, 50% normal

11. Pedigree: a diagram that shows relationships within a family; typically shows the occurrence of a particular trait