BISC 219/F10: Lab 7
Lab 7: Series2 Forward Genetics Project- SCORE!
Mapping: Count all adult and L4 progeny from one plate, scoring as either wild type , Dpy , Unc or Dpy Unc. Also score the second plate unless you have counted >100 total animals. Remember to remove each animal after you have determined its phenotype.
How would you get the single mutant class if you started with linked genes d u/+ + (genotype of the male) and d u/ d u (genotype of the hermaphrodite parent)?
You will determine map distances using the formula: RF (recombinant frequency) =the number of single mutants (both dpy and unc single mutants) divided by the total number of worms counted * 100 (to obtain RF in % recombinants and thus in map units).
Congratulations! You now have calculated the location of the dpy mutation in map unit distance away from your reference linked unc gene on the a particular autosome. To check your location (and the accuracy of your recombination frequency relationship to map units), enter the linked uncgene name into the C. elegans database: | Wormbase at http://www.wormbase.org Wormbase. Scroll down and click on Mapping Data and find the gene that is your calculated number of map units away from the linked unc gene. (Remember that you will have to look in both directions on the chromosome). Is the dpy gene that you found allelic in complementation analysis at this map location? Yes? Terrific! If not, your next step would be to see what is known about that location on the chromosome and see if what's known fits in at all with your observations. If it does, great and, if not, you have some thinking to do. (You will NOT write a paper about "sources of error" in your experimental design or your execution of the experiment!!!!)
Enter your dumpy gene name into the box at the top of the page and click Search. It will either bring you directly to that page or it will bring you to a page with mutiple hits - click on the link that provides a definition for what the gene does.
On this new page should be all the known information about this particular gene. Its name, who named it, what the gene encodes - if that is known, and much more. At the bottom will be a list of references - or a link to a list of references. Find out the function of this gene.
Spend some time with Wormbase and marvel at all the hard work and years of research that went into discovering all this information about this tiny little nematode that causes us no harm (non-parasitic). Why do you think so many smart people have devoted so much of their time and energy to working out the genetics of "appearance or movement challenged" little worms? We will talk more about model organisms and the power of functional and comparative genomics in our next series.
Links to Labs& Project Info
Series1:
Worm Info
Lab 1: Worm Boot Camp & Sex-Linked or Autosomal Start
Lab 2: Sex-Linked or Autosomal Finale
Series2:
Background: Classical Forward Genetics and Gene Mapping
Lab 2: Mutant Hunt
Lab 3: Linkage Test Part 1
Lab 4: Linkage Test Part 2, Mapping and Complementation
Lab 5: Mapping Con't
Lab 6: Finish Complementation; Mapping Con't
Lab 7: Complete Mapping: Score
Series3:
Schedule of Reverse Genetics Project
RNAi General Information
Media Recipes
Lab 5: Picking your gene to RNAi
Lab 6: Cloning your gene of interest
Lab 7: Picking your transformant
Lab 8: Plasmid purification and transformation
Lab 9: Induction of bacteria for RNAi
Lab 10: Scoring your worms and RNA purification
Lab 11: RT PCR reactions
