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Unformatted text preview: we cross a dihybrid heterozygous plant with another plant that is homozygous purple stem and heterozygous for the leaf trait. Determine the expected ratios for the phenotypes of the offspring. Suppose a class observed that there were 234 plants that were purple stem/green leaves and 42 that were purple stem/yellow leaves. Conduct a chisquare to determine whether the data is consistent with your expected ratio. Using your understanding of genetics, what might be one reason why the class got these results? HardyWeinberg Review Formulas: p 2 + 2pq + q 2 = 1 p = frequency of the dominant allele in a population p + q = 1 q = frequency of the recessive allele in a population Example problem: For people, being right handed (R) is the dominant trait over being left handed (r). Suppose there is a sample of 20 people that reveals the following genotypes: (RR) (Rr) (RR) (Rr) (rr) (Rr) (RR) (RR) (Rr) (RR) (Rr) (rr) (Rr) (Rr) (RR) (RR) (Rr) (RR) (rr) (Rr) a. What percentage of the people are right handed? Left handed? b. Find p and q and interpret each in the context of the problem. Now suppose that we took another sample of 10 people. This time we only know their phenotypes. (Right) (Left) (Right) (Right) (Right) (Right) (Right) (Right) (Left) (Right) c. What percentage of the people are right handed? Left handed? c. Can you find p and q exactly? Why? d. Estimate p and q and interpret each in the context of the problem. e. Estimate how many of the right handed people are homozygous and how many are heterozygous. Formulas: p 2 + 2pq + q 2 = 1 p = frequency of the dominant allele in a population p + q = 1 q = frequency of the recessive allele in a population Example problem: In 1990 the East Kentwood High School student body was made up of 90% right handed students. Being right handed (R) is the dominant trait over being left handed (r). a. What is p and q for the population of 1990 East Kentwood High School students. Interpret each. b. Find the percent of the student body in 1990 that are homozygous right handed, heterozygous right handed, and left handed. Fast forward to today at East Kentwood. Mr. V. took a random sample of 100 East Kentwood students today and found that 18 of them were left handed. c. What are the new p and q values? How do they compare with the values from 1990? There are many reasons why this apparent change could have occurred. Come up with an East Kentwood example for each: Small Population Size: Nonrandom Mating: Mutations: Gene Flow: Natural Selection: Surface Area to Volume and Water Potential Review 1) Cells throughout the world have variable shapes and sizes. Because of this, and because structure is designed around function, certain shapes are optimal for certain processes. Analyze the following cells (units not to scale), and determine the following… Cell 1 (spherical) where the radius is 3 mm Cell 2 (flat and rectangular) where the height is 0.5mm, length is 4mm, width is 2mm A) What is the surface area to volume ratio of both cells?...
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 Fall '11
 Boyle
 Biology, Demography, Standard Deviation, Population Ecology, Zygosity

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