Question

9) In an attempt to better understand GAL gene regulation, an undergraduate researcher performed a series of mating experiments between haploid yeast strains that contained different mutations in the gal regulatory genes, generating the different diploid genotypes shown below ! (note, for each strain, only the changes, relative to wild-type, are indicated; assume that all other genes are wild-type). For each strain, indicate whether the gal genes would be ON or OFF when grown with or without galactose (assume that glucose is NOT added) (16 points) Diploid strain genotypes With Galactose Without Galactose wild-type/wild-type AGAL4/AGAL4 MIG1 (Mig1 always in the nucleus)/wild-type

Answer 1

With gal. Without gal

1. Wild type. +. -

2.∆gal4 -. -

3. Mig1. +. -

4∆ gal80/wild type. +. -

∆gal4/ wild type

5. ∆ gal80. +. +

6. Gal3/ wild type. +. -

Gal4 is activator while gal 80 is repressor

Gal 3 is coactivator and mig is repressor

Hope it's clear..thanks