Page 22 Problem 2.1 What is the probability that a particular allele has at least one copy in the next generation? The surprising answer quickly becomes independent of the population size as N increases. Note: The probability that a particular allele has at least one copy in the next generation is equal to one minus […]
Page 16 Problem 1.7 Derive the Hardy-Weinberg law for a sex-linked locus. Let the initial frequency of A1 in the females be pf and in the males, pm. Follow the two alleles frequencies in successive generations until you understand the allele-frequency dynamics. Then, jump ahead and find the equilibrium genotype frequencies in females and males.
Page 16 Problem 1.6 Perform a Chi-squared test for agreement of the data in Table 1.2 with the predictions of the Hardy-Weinberg law. Note: Table 1.2 see #note Population Genetics A Concise Guide (4) Run Chi-squared test in Python: Output:
Page 15 Problem 1.5 Graph the ratio of the frequencies of A1A2 heterozygotes to A2A2 homozygotes as a function of q using both the exact and the approximate formulae. Note: Exact formula by using Python: Output: Approximate formula by using Python: Output:
Page 15 Problem 1.4 Graph the frequencies of homozygotes and heterozygotes as a function of the allele frequency, p. At what allele frequency is the frequency of heterozygotes maximized? Note: According to the Hardy-Weinberg law, p2+2pg+q2=1, where 2pq is the frequency of heterozygotes. q=1-p, so to maximize 2pq is to maximize 2p(1-p), so p=0.5. When
Page 14 Problem 1.3 Hardy-Weinberg frequencies in dioecious species may be investigated in an entirely different way. Let the genotype frequencies in females be x11, x12, and x22, and in males, y11, y12, and y22. Enumerate all nine possible matings (A1A1 female by A1A1 male, A1A1 female by A1A2 male, etc.) and calculate the frequencies
Page 12 Problem 1.2 Calculate the frequency of the three alkaline phosphatase alleles in the English population. Genotype Number Frequency Expected SS 141 0.4247 0.4096 SF 111 0.3343 0.3507 FF 28 0.0843 0.0751 SI 32 0.0964 0.1101 FI 15 0.0452 0.0471 II 5 0.0151 0.0074 Total 332 1.0000 1.0000 Table 1.2: The frequencies of alkaline
Page 11 Problem 1.1 How many different genotypes are there at a locus with n alleles that differ by state? You already know that there is one genotype at a locus with one allele and three genotypes at a locus with two alleles. Continue this with three, four, and more alleles until you divine the
Page 9 It’s not a particularly precise estimate because of the small sample size. A rough approximation to the 95 percent confidence interval for a proportion is where pĚ‚ is the estimate of the proportion, 0.55 in our case, and n is the sample size. Thus, the probability that the population allele frequency falls within
Page 5 The number of polymorphic sites within melanogaster and fixed differences between melanogaster and erecta are summarized in the folloing table: Polymorphic Fixed Silent 13 26 39 Replacement 1 10 11 14 36 50 Note: 2 X 2 Contingency Chi-square calculation: P > 0.05 (degrees of freedom dof = 1), thus that the two