Lab 5

Goals of the lab:

• Score complementation testing results to determine whether our gene of interest is allelic to any known genes.
• Learn more about the potential causes of our phenotype by reading and discussing a scientific article

Complementation: Examining Phenotypes

In the last lab, we crossed males carrying our mutant allele with hermaphrodites homozygous for a reference mutation.

Before examining your plates, consider the following questions:

• If our mutation is allelic to the reference mutation, what percentage of the progeny should show the mutant phenotype?
• If our mutation is non-allelic to the reference mutation, what percentage of the progeny should show the mutant phenotype?
• If you saw the mutant phenotype only in hermaphrodite offspring, what might explain such a result? (Hint: how could mutant hermaphrodites be produced other than a successful cross?)

TO DO:

• Next examine all three of your complementation crosses for mutant worms.
• You do NOT need to score crosses that have only wild type worms, but do move some of these males to a separate plate to take a picture. This will be your evidence for complementation, and you'll need the images for your homework.
• For plates that have mutant worms, score only ADULT MALES. Remember to move around the plate randomly to score. Before you begin flaming, move some mutant males to a separate plate to take a picture as evidence.

Finding out more about our gene of interest

If you discovered that one of the reference dpy strains was allelic to your mutation, congratulations! You now know the name of your mutated gene. Enter this name into the box at the top of the page in Wormbase and click Search. This page is a great resource for basic overview information about the gene and the protein it encodes, along with references for further investigation.

You can check previous research for the number of map units between the gene of interest and reference gene. Scroll down the "Page Content" column on the left and click on Mapping Data. Set the drop down menu to "Show 100 entries." What is the published map distance between our gene of interest and the linked unc reference gene? How closely does it match our experimental distance? What might cause any difference between our distance and the published distance(s)?

There are likely to be several different functionally significant areas on the gene that is associated with your mutation. Our mapping and DNA sequencing work next week will tell you more about the mutation and may help you pinpoint a functionally significant part of the gene.

Journal club

For the duration of the lab period, we will discuss a journal article about the interactions between various genes in the formation of the C. elegans cuticle.