Celegans_gen Flashcards
epistasis purpose
group genes by pathway and determine their order
intermediate phenotype - producing pathway
where what we observe would normally be consumed in WT but is present in the mutant. each step occurs in order for a function to proceed, otherwise you get intermediate phenotypes
terminal phenotype - producing pathway
pathways that control an ongoing process with a default output but once a signal is present the output changes
T/F. Epistatic genes are always downstream
False, they are downstream when considering a terminal phenotype, but upstream with an intermediate phenotype
why do you need mutants with opposite phenotypes to do epistasis analysis?
because you cannot determine interactions if the output to knockdowns of pathway genes is the same
T/F. Gene with mutant similar to double mutant is epistatic to the other gene
True
What creates C. elegans males
nondisjunction occurs in one in a thousand meioses, making a gamete with no X. XO male can only make sperm, XX are hermaphrodites
how do you get more males?
cross hermaphrodites to males to get 50/50 spit, although you will still get some XX self progeny
hawaiian strain of C. elegans
has a SNP every kb, allows for simultaneous mapping and cloning of a gene, more rapid ID of mutant alleles
benefits of a forward genetic screen
unbiased hits, with a variety of mutant types
drawbacks of a fwd screen
have to map your mutant
benefits of a reverse screen
you know what your mutant is
drawbacks of a reverse screen
you’re limited to predicted genes, can only do knockdowns
morpholinos
like siRNAs - prevent translation of mRNA, are ~25bp, contain nitrogenous bases allowing for basepairing - but have a morpholine ring instead of a ribose sugar, allowing for nuclease resistance. steric blockage of ribosome
