1. Quantitative Traits

2. Quantitative Traits Distribution of Corn Ear Lengths

3. Mendelian Explanation of a Quantitative Trait Very small : Small : Medium : Large : Very Large 1 4 6 4 1

4. Study Question 3 How many discrete lengths would you predict to be possible if there were four identical Height genes?

5. Complementation Multiple Infection Multiplicity of Infection Phage/Hosts

6. Complementation Failure to Complement

7. Complementation

8. Study Question 4 5 mutants of phage T2 Mutants forms tiny plaques Complementation tests - coinfect E. coli with pairs How many genes are required for the wildtype phenotype?

9. Study Question 5-7 Cross female #34 extra hairy x male #43 (Curly hair) Possible genotypes of parents? Genotypes of F 1 progeny? #34: EE x #43: CC EC One gene hypothesis #34: EE ++ x #43: ++ CC E+ C+ Two gene hypothesis #34: X E X E ++ x #43: X + Y CC Two gene hypothesis/one X-linked X + X E C+ X E Y C+

10. Recombination Nicked strand invades other chromosomeOne strand nickedHomologous chromosomes pairOther strands breakRecombination complete

11. Recombination No change (sequences are identical except for sites of mutation)

12. Recombination Two novel DNA’s, different from parents

13. Complementation vs Recombination Complementation Recombination acts through protein acts through DNA temporary permanent efficient rare useful to define genes useful to map genes