EXAMPLE- Writing assignment 1- Scenario_hypothesis_references

EXAMPLE- Writing assignment 1- Scenario_hypothesis_references

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Unformatted text preview: BIOL 1209 EXAMPLE ­ Writing assignment 1: Scenario/hypothesis/references Scenario: Natural selection A population of squirrels recently had a mutation in the gene for fur color. This mutation results in individuals that are homozygous recessive in having a white fur color. Unfortunately the white fur color is easily recognized by predators and results in increased predation rates for homozygous recessive individuals (Stencel & Ghent 1987). I am interested in determining whether frequencies for dominant (dark fur) and recessive (white fur) alleles change due to a selection against the white phenotype. Null hypothesis: There will be no difference in allele frequencies of dark (A) or albino (a) color fur regardless of fitness differences between the genotypes over time. Alternative hypothesis: There will be a difference in allele frequencies between dark (A) and albino (a) color fur because of the fitness differences between the genotypes over time. Prediction: The lower fitness value for the homozygous recessive genotype (aa, albino fur) of the white squirrels will result in an increased frequency of the dominant allele (A) over time because selection is acting upon the recessive allele, thus increasing frequency of the dominant. POP G settings: Control: Treatment: Population size = 10,000 Population size = 10,000 Fitness values Fitness values AA = 1 AA = 1 Aa = 1 Aa = 1 aa = 1 aa = 0.7 Mutation Rate Mutation Rate A→a = 0 A→a = 0 a→A = 0 a→A = 0 Initial allele frequency = 0.5 Initial allele frequency = 0.5 Number of generations = 1000 Number of generations = 1000 Citation: Stencel, J.E. & Ghent, A.W. (1987). Analyses of Annual Surveys of White and Gray Squirrels (Sciurus carolinensis) in Olney, Illinois, 1977 ­1986. American Midland Naturalist, 118(2): 251 ­257 ...
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This note was uploaded on 03/20/2012 for the course BIOL BIOL 1209 taught by Professor Gregg during the Spring '09 term at LSU.

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