Evo Bio FINAL (Spring 2010)

Evo Bio FINAL (Spring 2010) - FINAL EXAM(Spring 2010 You...

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FINAL EXAM (Spring 2010) You scored 20 out of 36 Question 1 Your answer is CORRECT. A QTL mapping study reveals three distinct, distantly located loci that contribute to variation in the growth rate of sexual snails. The effects of these loci are non-additive (i.e., epistatic or interactive or V I ) . Castrating parasites impose strong directional selection on development rate, favoring individuals that reach reproductive age rapidly (slow developers become infected more frequently than rapid developers). In one lake containing thousands of snails, there is high allelic variation at each of the three loci, yet the average age of first reproduction does not change over time. Which of the following is the most likely explanation for this? a) The parasites impose negative frequency-dependent selection on development rate which produces cycles and thus cannot change the average age at first reproduction over time. b) Epistasis among the three loci contributing to development rate (V I ) means that this variation cannot contribute to the response to selection because recombination prevents the loci from being inherited as a single unit. c) Positive directional selection on development rate is opposed by negative directional selection on fitness, producing net stabilizing selection. d) Linkage disequilibrium reduces the heritability of the three loci. e) Asexual reproduction does not allow rapid evolution of new trait values, such as an increase in size, because it takes a long time for the favored alleles to appear in a single clone. Question 2 Your answer is CORRECT. Two loci exist on different chromosomes; the A locus is on chromosome one whereas the B locus is on chromosome two. The relative fitness of the different genotypes is shown below, as is the location of the loci on each chromosome. Given this information, what can you say is true?
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a) The fitness effects of the A and B loci are independent. b) Epistasis for fitness between the A and B loci produces linkage disequilibrium between them. c) Hitchhiking between the A and B loci produces linkage disequilibrium between them. d) Background selection between the A and B loci produces linkage disequilibrium between them. e) Physical proximity between the A and B loci produces linkage disequilibrium between them. f) Linkage disequilibrium cannot form between these loci because they are on different chromosomes. g) Recombination between the A and B loci prevents linkage disequilibrium from forming between them. h) none of the above. Question 3 Your answer is INCORRECT. Panel 1 below shows a complex fitness function for a phenotype. Panel 2 shows frequency distributions for five populations (A, B, C, D, and E). Based on these panels, which population or populations experience the strongest natural selection?
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a) Population A b) Population B c) Population C d) Population D e) Population E f) Populations B and D are tied for the strongest selection pressure g) Populations C and E are tied for the strongest selection pressure
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This note was uploaded on 07/27/2011 for the course BIOL 3306 taught by Professor Zufall during the Spring '09 term at University of Houston.

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Evo Bio FINAL (Spring 2010) - FINAL EXAM(Spring 2010 You...

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