Quantitative Traits Quantitative Traits Distribution of Corn Ear

Quantitative Traits

Quantitative Traits Distribution of Corn Ear Lengths

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

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

Complementation Multiple Infection Multiplicity of Infection Phage/Hosts

Complementation Failure to Complement

Complementation

Study Question 4 • 5 mutants of phage T 2 • Mutants forms tiny plaques • Complementation tests - coinfect E. coli with pairs • How many genes are required for the wildtype phenotype?

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

Recombination Nicked One Homologous Other Recombination strands strand nicked chromosomes break invades complete other pair chromosome

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

Recombination Two novel DNA’s, different from parents

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