Yeast_genetics Flashcards
point of complementation analysis
to determine if mutant genes are in the same gene
T/F. Complementation tests are tests of function
True
what would you do to confirm a complementation test?
a linkage analysis - which is a test of position
what is the tetrad segregation pattern called that results in two recombination events in which all 4 haploids are recombinants?
non-parental ditype
what is the tetrad segregation pattern where all four haploids look like one of the original parental cells?
parental ditype
tetratype
where segregation patterns produce two recombinant cells and two parentals (single recombination event)
what is the tetrad segregation pattern for two linked genes?
PD > T > NPD, recombination unlikely as they are in the same or neighboring genes
what is the tetrad segregation pattern for two unlinked genes?
PD = NPD > T, since recombination is likely, PD = NPD due to random segregation
T/F. Linkage analysis relies on meiotic recombination
True
what is a suppressor?
a compensatory mutation that restores WT phenotype
why are suppressors handy?
to find genes in a pathway?
intragenic suppressors?
suppressor in same gene - either true revertant, or second site mutation
extragenic suppressor types (5)
interaction, bypass, epistatic, mass action, dosage, nonsense
interaction suppressor
allele specific, does not rescue a null
bypass suppressor
rescues a null, can also provide novel function to protein
epistatic suppressor
type of bypass suppressor, rescues a null
dosage suppressor
rare, restores balance in a system
mass action suppressor
type of dosage, stabilizes mutant by interaction
suppressors you might miss (4)
duplicated genes, essential genes, small genes, wrong assumption about phenotype
synthetic lethality
where single mutants are viable, but double are lethal in the same cell
SGA
synthetic genetic array, yeast specific - a method to screen genome wide for synthetic interactions that cause a diff growth pattern than expected
how do you predict how large a mutant cross colony should be?
multiplicative model, if Ab = 0.5 and aB = 0.5, then the cross of the two should be 0.25
can’t lose plasmid (yeast version)
deletion or mutation of interest covered by a URA3 plasmid, transform/mutagenize/plate on non-selective media, then when you replica plate onto 5-FOA the synthetic lethal colony will not grow on 5-FOA bc of the URA3 gene
can’t lose plasmid (bacterial version)
deltion or mutant covered by unstable plasmid containing LacZ and ampR, perform transposon mediated mutagenesis, insertion of kanR, then screen library for kan, IPTG expressing LacZ, and pick colonies that turn blue with synthetic lethal plasmid
three techniques for identifying suppressors
linkage analysis, whole genome sequencing, tn-seq
high copy plasmid screen
where you transform mutant with high copy genomic library, each cell getting only one plasmid and each plasmid overexpressing one gene. plate so only suppressors will grow
