BISC 219/F10: Lab 2: Difference between revisions
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== Lab 2: Culmination of Gene Linkage == | == Lab 2: Culmination of Gene Linkage == | ||
#Examine each plate of F2 progeny. If you chose only L4 hermaphrodites you should only see hermaphrodite progeny. If you have a lot of males on your plates you chose young adult worms rather than L4's - see your instructor.<br> | #Examine each plate of F2 progeny. If you chose only L4 hermaphrodites, as instructed,you should only see hermaphrodite progeny. If you have a lot of males on your plates, you probably chose young adult worms rather than L4 hermaphrodites's. That's a problem - see your instructor.<br> | ||
#For each cross you | #For each cross, you should count and examine a random sample of 100 worms. The mutant worms may be smaller and not move as well as the wild type worms. Look around your plate to get a quick assessment of the population.<br> | ||
#Record in your lab notebook the number of WT, Dpy, Unc or Dpy Unc mutants by examining the phenotype as you remove each animal from the plate (flame the pick | #Record in your lab notebook the number of WT, Dpy, Unc, or Dpy Unc mutants by examining the phenotype as you remove each animal from the plate. (Be sure to flame the pick after removing each worm.) If the genes responsible for the mutations are unlinked, you should see WT's (+/+;+/+), Dpy’s (d/d;+/+), Unc’s(+/+;u/u) and Dpy Unc’s (d/d;u/u) in a ratio of 9:3:3:1. If linked, you should see a greater proportion than expected of Dpy Unc’s (d u/d u) double mutants vs Dpy or Unc single mutants among the mutant hermaphrodite progeny.<br> | ||
<br> | <br> | ||
You should now be able to conclude which strain is autosomal and linked, autosomal and unlinked | You should now be able to conclude which strain is autosomal and linked, which is autosomal and unlinked, which strain has an x-linked gene, and which gene, Dpy or Unc, is sex-linked in the X-linked strain.<br> | ||
<br> | <br> | ||
'''**See Assignments page for instructions on write-up.''' | '''**See Assignments page for instructions on write-up.''' | ||
Revision as of 08:37, 12 August 2010
Lab 2: Culmination of Gene Linkage
- Examine each plate of F2 progeny. If you chose only L4 hermaphrodites, as instructed,you should only see hermaphrodite progeny. If you have a lot of males on your plates, you probably chose young adult worms rather than L4 hermaphrodites's. That's a problem - see your instructor.
- For each cross, you should count and examine a random sample of 100 worms. The mutant worms may be smaller and not move as well as the wild type worms. Look around your plate to get a quick assessment of the population.
- Record in your lab notebook the number of WT, Dpy, Unc, or Dpy Unc mutants by examining the phenotype as you remove each animal from the plate. (Be sure to flame the pick after removing each worm.) If the genes responsible for the mutations are unlinked, you should see WT's (+/+;+/+), Dpy’s (d/d;+/+), Unc’s(+/+;u/u) and Dpy Unc’s (d/d;u/u) in a ratio of 9:3:3:1. If linked, you should see a greater proportion than expected of Dpy Unc’s (d u/d u) double mutants vs Dpy or Unc single mutants among the mutant hermaphrodite progeny.
You should now be able to conclude which strain is autosomal and linked, which is autosomal and unlinked, which strain has an x-linked gene, and which gene, Dpy or Unc, is sex-linked in the X-linked strain.
**See Assignments page for instructions on write-up.
