1. Biology 122

2.  Topics Sex linked traits Sex influenced traits Polygenics Epistasis

3.  What is a trait?  Review – Google “Learn Genetics”, click on “Tour of the Basics” and the “What is a trait?” link

4.  Objectives Define sex-linked trait Explain and provide examples of different types of sex linked traits  Online exercise – research sex linked traits

5.  What is a sex linked trait?  Are sex linked disorders more common in males or females? Why?  There are 3 types of sex linked traits X-linked recessive  What are x-linked recessive traits?  Are they more common in males or females? Why?  Will affected dad’s pass these on to their sons? …Daughters? What about affected mothers?  Provide two examples of x-linked recessive traits.

6. X-linked dominant  What are x-linked dominant traits?  Are they more common in males or females? Why?  Will affected dad’s pass these on to their sons? …Daughters? What about affected mothers?  Provide two examples of x-linked dominant traits.

7. Y-linked traits  What is a y-linked trait?  Who can have a y-linked trait? Is it always expressed?  How often is it passed from one generation to the next? Why?