Announcements for MCB 110L Office Hours (starting Mon., 28 Jan.) : M 12-1 PM Jane GPB 203

1. Announcements for MCB 110L Office Hours (starting Mon., 28 Jan.): M 12-1 PM Jane GPB 203 Tu 2-3 PM Dale GPB 109 W 12-1 PM Jesse GPB 201 W 12-1 PM Maumita GPB 203 F 12-1 PM Joo Eun GPB 203 Th 3-4 PM Jeremy 526 Barker

2. Life Cycle of the Budding Yeast, Saccharomyces cerevisiae

3. Genetic Nomenclature Conventions for Saccharomyces cerevisiae Normal (“wild-type”) locus: YFG1 Loss-of-function (hypomorphic) allele: yfg1-1 (point mutation) yfg1-∆1 (null mutation) Gain-of-function (hypermorphic) allele: YFG1-20 Alteration-of-function (neomorphic) allele: YFG1-54 A normal, hypermorphic or neomorphic allele is dominant over a hypomorphic allele: YFG1/yfg1 Presence and status of an episome or non-Mendelian determinant in brackets: [YCp352], introduced DNA plasmid [cir+], endogenous 2 m DNA circle [rho-plus = +], functional mitochondrial DNA [psi+], presence of prion form of Sup35 (yeast eRF3) [KIL-k1], endogenous dsRNA viroid encoding secreted toxin

4. FCP1 [TFIIF-associated Rpo21 carboxy-terminal domain (CTD) phosphatase] Strain YSA1: MATfcp1∆::LEU2TRP1:: fcp1-2ts ade2 his3 leu2 trp1 ura3 [YCp-FCP1, URA3] The FCP1 gene is essential for S. cerevisiae cell viability. (mutations in the orthologous human gene product, CTDP1, causes congenital cataracts with facial dysmorphism and neuropathy)

5. The Concept of a Genetic Cross e.g., MATamutation a X MATmutation b What can we learn from such crosses? • Assess whether mutation a is dominant or recessive to the corresponding WT locus, and assess whether mutation b is dominant or recessive to the corresponding WT locus (dominance test) • Determine whether mutation a and mutation b are likely to be alterations of the same gene (complementation test) • Map the relative positions of locus a and locus b by examining their segregation behavior in meiosis (tetrad analysis) • Generate a potentially useful double mutant (epistasis test)

7. MATa MAT

8. CEN3 642 bps a haploid: 747 bps  haploid: a/ diploid:

9. a a1 MATa1 = no ORF no. MAT2 = YCR039c MAT1 = YCR040w a1 a

10. A B C D E F G H I J K L M N O P

11. Systematic name for the FCP1 locus is YMR277w. Automatically tells you that the ORF encoded by the FCP1 gene is situated on the right arm of Chromosome XIII and transcribed in the direction away from CEN13.

12. a a1 MATa1 = no ORF no. MAT2 = YCR039c MAT1 = YCR040w a1 a

13. Available from Cold Spring Harbor Laboratory Press

14. The Concept of a Genetic Cross e.g., MATamutation a X MATmutation b What can we learn from such crosses? • Assess whether mutation a is dominant or recessive to the corresponding WT locus, and assess whether mutation b is dominant or recessive to the corresponding WT locus (dominance test) • Determine whether mutation a and mutation b are likely to be alterations of the same gene (complementation test) • Map the relative positions of locus a and locus b by examining their segregation behavior in meiosis (tetrad analysis) • Generate a potentially useful double mutant (epistasis test)