PS11_solutions

# PS11_solutions - 2 WW = 0 Ww = 31 ww = 251 n = 282 cats(can...

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Problem Set 11 Answer Key 1. SS = 26 Ss = 127 ss = 123 n = 256 S? = 27 N = 283 Step 1: Calculate allele frequencies Can't use usual formula to calculate allele frequencies, since don't know how many of the unknowns are heterozygotes, BUT are assuming that population is in HW equilibrium, so can use homozygous recessives to calculate q: q 2 = 103/283 0.364 q = 0.364 0.603 p = 1 – q = 1 – 0.603 = 0.397 Step 2: Calculate unknown genotypes Use allele frequencies & total number of cats (283) to calculate expected number for SS & Ss genotypes, then use these to determine genotypes of unknowns. SS = p2 * N = (0.397)2 * 283 45 Expect 45, but only have 26, so 45-26 = 19 unknowns have gentotype SS Ss = 2pq * N = (2)(0.397)(0.603) * 283 135 Expect 135, but only have 127, so 135 – 127 = 8 unknowns have genotype Ss Check: total unknowns = 27, 19 + 8 = 27, so we've assigned all our unknowns!

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Unformatted text preview: 2. WW = 0 Ww = 31 ww = 251 n = 282 cats (can choose to calculate p directly (frequency of W allele), or calculate q first) p = 31/(2 * 282) ≈ 0.055 OR q = (31 + (2 * 251))/(2 * 282) ≈ 0.945 p = 1 – q = 1 – 0.945 = 0.055 3. Males: OY = 26 oY = 78 n = 104 Females: OO = 13 Oo = 49 oo = 93 n = 155 Step 1: Calculate population allele frequencies q pop = (q male + 2(q female ))/3 q male = 78/104 = 0.75 q female = (49 + (2 * 93))/(2 * 155) ≈ 0.758 q pop = (0.75 + (2 * 0.758))/3 ≈ 0.755 p pop = 1 – 0.755 = 0.245 Step 2: Calculate HW genotype frequencies OY = ½ * p pop = 0.245 * 0.5 = 0.1225 oY = ½ * q pop = 0.755 * 0.5 = 0.3775 OO = ½ * p pop 2 = (0.245)2 * 0.5 = 0.03 Oo = ½ * 2p pop q pop = 2 * 0.245 * 0.755 * 0.5 = 0.185 oo = ½ * q pop 2 = (0.755) 2 * 0.5 = 0.285 • Check: add all genotype frequencies to verify they sum to 1...
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PS11_solutions - 2 WW = 0 Ww = 31 ww = 251 n = 282 cats(can...

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