WS1 Drosophila - MMJ edit(1)

docx

School

University of South Carolina *

*We aren’t endorsed by this school

Course

301

Subject

Biology

Date

Apr 3, 2024

Type

docx

Pages

Uploaded by lmarks422

Drosophila Population Genetics Worksheet Name_____________________ Biology 301L The genetic simulation program is available at https://www.radford.edu/~rsheehy/Gen_flash/popgen/ Ecologists often use mathematical models to understand the dynamics of population change. In this exercise you will 1) investigate how initial allele frequency, relative fitness, and Mendelian genetics affect evolution in a population; 2) use a model to make predictions of final allele frequency for our Drosophila evolution experiment; 3) create testable hypotheses for the experiment; and 4) create a figure showing your predicted/hypothesized results. The models used here include the following parameters: • population size (N ) = the number of individuals in the population (number of individuals) at generation 0. This parameter ranges from 1 to 10 000. • initial allelic frequency (p) = the proportion of the initial population that has the p allele. This parameter ranges from 0.0 to 1.0. • Generations (runtime) = the maximum number of generations to run the model simulation. Note: the actual number of generations the model completes may be less than the runtime if the population reaches fixation before the number of generations you designated. • w = relative fitness . This parameter must be assigned independently by you to all three genotypes. Remember, fitness acts on the phenotype, not the genotype directly. Preparatory Exercises Using the following scenario, run the population simulator to answer these questions. In peacocks, a long tail diminishes ability to escape from coyotes. Assume tail length is controlled in a simple Mendelian fashion, and longer tails are homozygous for the recessive allele (l), and short tails are either homozygous for the dominant allele (L) or heterozygous. Answer the following preparatory questions based on a simulation using the following parameters: Population size (N) = 300 Initial allele frequency (p) = 0.5 Generations = 500 Fitness: w AA = 1.0 w Aa = 1.0 w aa = 0.1 Questions: 1. Run 5 simulations and record A) the allele frequency at 5 generations and B) the number of generations until the population reaches fixation. A. Average of all 5 simulations at generation 5: B. Average number of generations to fixation/loss, and which allele reaches fixation?

2. All coyotes have been shot. Thus, there is little predation on peacocks. (w aa = 0.9) . Run 5 simulations and record A) the allele frequency at generation 5, and B) the number of generations to fixation. A. Average of all 5 simulations at generation 5: B. Average number of generations to fixation/loss, and which allele reaches fixation? 3. Adjust the initial allele frequency (p) to 0.1. (Lots of long tails in the initial population). Adjust fitness to the original values for each genotype . Run 5 simulations and record: A) the allele frequency at generation 5 and B) the number of generations to fixation. What are the averages and what differences did you see when compared to the results of question 1? A. Average of all 5 simulations at generation 5: B. Average number of generations to fixation/loss, and which allele reaches fixation? Experimental Predictions Next, we will use models to make predictions for the experiment we are beginning today. Using the same models as above, input relative fitness values based on the table below. Record the proportion of p for generations 0, 1, 2, 3, 4, 5, and record the number of generations to fixation. Each model is a separate set of PopGen runs with the indicated selection coefficients. Use the values produced by the model to create a figure that illustrates our predicted results. I recommend recording all your values in the provided excel notebook on BB and submitting this in addition to this worksheet. Initial population parameters : Population size (N) = 100 Initial allele frequency (p = A1) = 0.2 (q) = 0.8 Selection Coefficients Why do we expect the heterozygote (w Aa ) to have the same selection coefficient as the wild-type homozygote (w AA )? Model 1 Predictions from PopGen Simulation number Proportion p at 0 generations Proportion p at 1 Proportion p at 2 Proportion p at 3 Proportion p at 4 Proportion p at 5 Generations To Fixation Model w AA w Aa w aa 1 1 1 0.4 2 1 1 0.8 3 1 1 1 4 0.8 0.8 1 5 0.4 0.4 1

generation generations generations generations generations 1 2 3 4 5 Model-predicted average allele frequency at generation 5: ( p ) = ( q ) = What is the average number of generations until one of the alleles (which?) reaches fixation? Model 2 Predictions from PopGen Simulation number Proportion p at 0 generations Proportion p at 1 generation Proportion p at 2 generations Proportion p at 3 generations Proportion p at 4 generations Proportion p at 5 generations Generations To Fixation 1 2 3 4 5 Model-predicted average allele frequency at generation 5: ( p ) = ( q ) = What is the average number of generations until one of the alleles (which?) reaches fixation? Model 3 Predictions from PopGen Simulation number Proportion p at 0 generations Proportion p at 1 generation Proportion p at 2 generations Proportion p at 3 generations Proportion p at 4 generations Proportion p at 5 generations Generations To Fixation 1 2 3 4 5 Model-predicted average allele frequency at generation 5: ( p ) = ( q ) = What is the average number of generations until one of the alleles (which?) reaches fixation?

Your preview ends here

Eager to read complete document? Join bartleby learn and gain access to the full version

Access to all documents
Unlimited textbook solutions
24/7 expert homework help

Model 4 Predictions from PopGen Simulation number Proportion p at 0 generations Proportion p at 1 generation Proportion p at 2 generations Proportion p at 3 generations Proportion p at 4 generations Proportion p at 5 generations Generations To Fixation 1 2 3 4 5 Model-predicted average allele frequency at generation 5: ( p ) = ( q ) = What is the average number of generations until one of the alleles (which?) reaches fixation? Model 5 Predictions from PopGen Simulation number Proportion p at 0 generations Proportion p at 1 generation Proportion p at 2 generations Proportion p at 3 generations Proportion p at 4 generations Proportion p at 5 generations Generations To Fixation 1 2 3 4 5 Model-predicted average allele frequency at generation 5: ( p ) = ( q ) = What is the average number of generations until one of the alleles (which?) reaches fixation? Based on your knowledge of our experimental system, formulate a hypothesis for each population cage about the relative selection coefficient of the vestigial flies (w aa ). In other words, do you expect the selection coefficient for vestigial flies to be higher, lower, or about the same in the cage with simulated predation compared to the other cage? [4pts, 2 per hypothesis]

Cage with NO simulated predator [5pts, 1 per question] Which of the 5 models do you expect to most closely match the population? Predicted allele frequency at 5 generations (from selected model) : ( p ) = ( q ) = If observed data match predicted data at generation 5, then how many generations would you predict the population to take for one allele to reach fixation and the other to be lost? Which allele do you expect to eventually reach fixation? What biological mechanism is responsible? Cage with simulated predator [5 pts, 1 per questions] Which of the 5 models do you expect to most closely match the population? Predicted allele frequency at 5 generations (from selected model) : ( p ) = ( q ) = If observed data match predicted data at generation 5, then how many generations would you predict the population to take for one allele to reach fixation and the other to be lost? Which allele do you expect to eventually reach fixation? What biological mechanism is responsible? Prepare and attach a graph that has 5 lines (plus confidence intervals), one for each of your predictive PopGen models. In the caption, point out which lines you expect to represent each of your caged populations and why. [6pts]

Related Documents

Week 3 Digestion and Electrophoresis Practical Methodology 23.docx

FINAL_LABS_BIO252_Online_Labs_BIOS252_Week_1_Online_Muscular_System_.docx

HW4.pdf

3.3 - Maximal Fick with ANSWERS.docx

3.2 - Matching O2 delivery to O2 demand with ANSWERS.docx

John Kuriyan, Boyana Konforti, David Wemmer - The Molecules of Life_ Physical and Chemical Principle

WS2 - BE Data Collection MMJ edit(1).docx

WS6_Water_Qual_CS.docx

BE Data Analysis handout.docx

Worksheet 7 mark and recapture - MMJ edit(1).docx

WS5 - BE Data Analysis - MMJ edit.pdf

WS9 - Stream Biodiversity.docx

Recommended textbooks for you

Human Heredity: Principles and Issues (MindTap Co...

Biology

ISBN:9781305251052

Author:Michael Cummings

Publisher:Cengage Learning

Comprehensive Medical Terminology

Nursing

ISBN:9781133478850

Author:Jones

Publisher:Cengage

Intro To Health Care

Health & Nutrition

ISBN:9781337338295

Author:Mitchell

Publisher:Cengage

3-2-1 Code It

Biology

ISBN:9781337660549

Author:GREEN

Publisher:Cengage

Biomedical Instrumentation Systems

Chemistry

ISBN:9781133478294

Author:Chatterjee

Publisher:Cengage

Concepts of Biology

Biology

ISBN:9781938168116

Author:Samantha Fowler, Rebecca Roush, James Wise

Publisher:OpenStax College

SEE MORE TEXTBOOKS

Recommended textbooks for you

Human Heredity: Principles and Issues (MindTap Co...
Biology
ISBN:9781305251052
Author:Michael Cummings
Publisher:Cengage Learning
Comprehensive Medical Terminology
Nursing
ISBN:9781133478850
Author:Jones
Publisher:Cengage
Intro To Health Care
Health & Nutrition
ISBN:9781337338295
Author:Mitchell
Publisher:Cengage
3-2-1 Code It
Biology
ISBN:9781337660549
Author:GREEN
Publisher:Cengage
Biomedical Instrumentation Systems
Chemistry
ISBN:9781133478294
Author:Chatterjee
Publisher:Cengage
Concepts of Biology
Biology
ISBN:9781938168116
Author:Samantha Fowler, Rebecca Roush, James Wise
Publisher:OpenStax College