NEW - Fungal Genetics Teaching Software
aday at julian.uwo.ca
Sat Oct 22 16:33:44 EST 1994
Announcement - New Fungal Genetics teaching software
The Virtual Genetics Laboratory is an integrated series of highly
interactive experiments - follow a set of fungal mutants from isolation to
characterization to tests for allelism to mapping via random spore, tetrad
analysis and mitotic recombination tech niques. Perform the procedures on
screen just as you would in the lab - isolate and drag samples from mutant
colonies to test genotype, mix haploids in pairs to do complementation
tests, score colonies growing on replica plates etc, Each exercise is
preceded by an introduction clearly s etting out the purpose and goals of
the experiment. Help animations and brief theory summaries are provided
Exercise 1 Isolation and identification of 3 auxotrophic mutants. You are
presented with a pair of replica plates following mutagen treatment. Pick
off cells from a mutant colony, inoculate them on minimal medium, then
test 8 potential growth factors to identify the requirement. Repeat with
remaining two mutants.
Exercise 2. Analysis of mutants with similar phenotypes - Biochemical test
to see which are allelic. You are given 10 arginine-requiring mutants.
Inoculate each to minimal medium, then test 4 precursors of arginine to
see which support growth. Deduce which of the genes in the known arginine
pathway are mutant in each of the 10 strains.
Exercise 3. Analysis of mutants with similar phenotypes - Genetical test
to see which are allelic (Complementation Test). You are given 10
histidine-requiring mutants. Mate these in all possible combinations to
make diploids and record the phenotype of the diploid that is formed.
Deduce from this complementation data how many histidine- requiring genes
are present and which mutants are allelic. Help files feature an
animated-lesson covering the theory of complementation
Exercise 4. Mapping by random-spore techniques - 3-point cross You are
presented with a sample of 16 individual segregants from a 3-point cross
that have been replicated to 5 test media. Deduce the genotype of each in
turn, then using the much larger sample of segregants provided calculate
the % recombination for eac h gene pair, make a map and answer questions
about map distances, interference etc. 2 Help animations on the principles
and practice of mapping included
Exercise 5. Mapping using Tetrad Analysis - the same 3 mutants as in #4
plus a new orange colony colour marker. You are presented with a sample of
8 asci from a 4-point cross. i) Gene to centromere mapping - first score
each ascus for First division and Second division segregation - then using
data from a larger sample calculate the gene-to centromere distance for
each of the 4 markers. ii) Gene to gene mapping - now using the same
sample of 8 asci score them for PD, NPD or T-type tetrads and from the
larger sample estimate gene-to gene recombination for each of the 6
possible gene combinations. Using the combined data from exercises 4 a nd
5 build the best possible map for the 4 genes and their centromeres. Help
animation on Tetrad analysis included.
Exercise 6. Mapping via Mitotic Recombination - exploiting haploidization
and mitotic crossing- over to obtain further mapping data. You are given 9
segregants from a diploid fungus and asked to score them for i) ploidy ii)
different auxotrophic and drug resistance markers. The segregants are then
analysed for mapping information. A full length 'help' animation on
mitotic recombination is included. This topic makes students think about
what happens during mitosis and what wo uld happen if a rare
recombinational event occurred.
Program runs on PC computers running Windows 3.x and is also available
integrated into our very comprehensive animated Genetics text - Visual
Genetics - now used by over 100 institutions world-wide.
Program now available at modest cost.
For details contact:-
aday at julian.uwo.ca
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