Unformatted text preview: elves as needed. Thus, this mutation does not increase the fish fitness and is considered neutral. Answer Question 18. Methods: Similarly to the previous exercise, the population will go through three rounds of gene exchange. Once again, if you cannot find a fish to mate with, wait until the next turn. During the first allele exchange turn, your TAs will introduce randomly a mutation in a certain number of arbitrarily selected fish. However this time the rules have changed somehow due to the introduction of the mutation. Follow the new procedure that follows: 1.
2. 3. 78 Once you find a mate, write down both parental genotypes in table 4. Selection of blue locus alleles: Randomly select the blue locus alleles of the offspring as described before. Then: If the offspring has one of the mutant (B1) alleles it survives. If the offspring lacks one of the mutant alleles (no B1), it may not survive. To determine the fate of the offspring, flip a coin (heads=lives, tail=dies). If the offspring dies, go back to step 2 and re‐select randomly a new set of alleles for the blue locus. If the offspring lives or has the mutant allele, write the new offspring genotype in table 4. Selection of green locus alleles: Randomly select the green alleles as described before. Lab4 ‐ Microevolution Since the mutant does not have higher chances of survival, the offspring lives regardless whether it carries a mutant allele or not. Write down the offspring genotype for the green locus in table 4. 4. Select the genotype of the second offspring by repeating steps 2‐3. 5. Allow your fish to die, and allow the offspring to be born by taking the identity of one of the offspring as it has been determined in the previous steps (flip a coin to determine who will become offspring #1 and #2). 6. Once everybody in the lab is finished with the first round of allele exchange, find a new mate (different from the mate you have exchanged alleles with during the previous generation) and repeat steps 1‐6 for two more generations. Enter the genotypes of all offspring in table 4. Note: no more mutant alleles will be introduced by your TAs in the subsequent rounds of gene exchange. 7. When everybody has finished with the three rounds of gene exchange, write down your fish genotype for each generation on the blackboard. Answer Questions 19‐23. This exercise was modified from Winterer (2001). Am. Biol. Teach. 63(9) pp678‐687. Part II: Introduction to computer simulation of Population genetics using Populus. I‐ Populus basic instructions: Populus is a simulation of population biology software developed by Don Alstad at the University of Minnesota (http://www.cbs.umn.edu/populus/). Follow the instructions given by your demonstrators to run the software. The simulations we will use during this exercise are accessible from the “Model” menu. Each simulation model consists of two windows: the input windows in which you enter values for various parameters of the simulation, and the output window where the results are displayed. Both windows are resizable....
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- Fall '08
- TA, Blue locus