1. Characteristics

2. Pre-lab discussion  Independent assortment v. linked  Dichotomous v. continuous traits  Polygenic traits  correlation

3. Hypothesis (Write 3!)  Independent variable: a pair of traits  Dependent variable: number of classmates with traits  Predict: Linked or not?  One hypothesis for continuous traits, two hypotheses for dichotomous traits.

4. DATA:  Record ALL of your data in write-up  For the pairs you choose to test, record ALL class data.

5. Continuous traits:  Height:  Weight:  Arm Span:

6. Dichotomous traits  These will be analyzed with contingency tables: yes nono no

7. Tongue Rolling (T, t)

8. Attached Earlobes (E, e) e E

9. PTC Taste (P, p)

10. Sex (X,Y) XX xy

11. Dimpled Cheeks (D, d)

12. Dimpled Chin (C, c)

13. Widow’s Peak (W, w)

14. Bent Little Finger (L, l)

15. Double-Jointed Thumb (J, j)

16. Middigital Hair (H, h)

17. Freckles (F, f)

18. Hitchhiker’s Thumb (G, g)

19. Webbed Toes (W, w)

20. Wooly Hair (R, r)

21. Analysis Discuss scatterplot graph and the two contingency tables.

22. Questions 1.What are “polygenic” traits? Which traits in this lab are Polygenic? 2.What are “dichotomous” traits? 3.Dichotomous traits are controlled by single gene. Give four examples of these from the lab. 4.What does it mean for two traits to be “linked”? 5.According to your data, what other traits besides the ones you hypothesized about, do you think might be “linked”? 6.If you had to determine red hair and freckles, or blond hair blue eyes were linked, how would you do it?