Hardy-Weinberg Equilibrium Practice Problems

Hardy-Weinberg Equilibrium Practice Problems Answers: 1. a. 0.566 b. 0.434 c. 0.188 d. 0.492 2. a. 102 individuals b. 49.7% 3. a. 0.48 b. 0.36 c. 0.16 4. a. AA = 0.684; AB = 0.286; BB = 0.030 b. 0.827 c. 0.173 d. 1,350 individuals 5. a. 360 individuals ‘Bald’ : 640 individuals ‘with Hair’ b. B = 0.4; b = 0.6 c. BB = 0.16 / Bb = 0.48 / bb = 0.36 6. a. 0.059% c. 5.9 newborns d. 473 individuals (avg. 473.2 individuals) 7. a. Bb = 0.483 b. No c. 270 individuals should be brown (note this answer comes by using the frequencies from your Senior Project, NOT from the 2030 measurement) 8. a. IA1IA1 = 0.563; IA2IA2 = 0.0625 b. 450 individuals would be IA1IA2 genotype Hardy-Weinberg Equilibrium Practice Problems 1. A population of tropical parakeets contains 16 animals with yellow tail feathers and 34 animals with blue tail feathers. Blue tail feathers are the dominant trait in this population. Answer the following assuming that the population is under Hardy-Weinberg Equilibrium. a. What is the frequency of the yellow allele? b. What is the frequency of the blue allele? c. What is the frequency of birds that are homozygous for the blue allele? d. What is the frequency of heterozygotes in this population? 2. In one population of an endangered species with only 400 individuals, 98 of those individuals express the recessive phenotype for a particular genetic locus. a. How many individuals in that same population are homozygous for the dominant allele at this locus? b. What percent (%) of the population are heterozygotes at this locus? 3. Brown fur (B) is dominant to white fur (b) in a population of prairie voles. If there are 168 brown haired voles in a population of 200: a. What is the predicted frequency of heterozygotes at this locus? b. What is the predicted frequency of homozygous dominant at this locus? c. What is the predicted frequency of homozygous recessive at this locus? 4. A hypothetical population of 10,000 humans has 6840 individuals with the blood type AA, 2860 individuals with blood type AB and 300 individuals with the blood type BB. a. What is the frequency of each genotype in this population? b. Assuming that the population is in Hardy-Weinberg Equilibrium, what is the frequency of the A allele? c. Assuming that the population is in Hardy-Weinberg Equilibrium, what is the frequency of the B allele? d. If the next generation contained 45,000 individuals, how many individuals would have blood type BB, again assuming the population is in HardyWeinberg equilibrium? 5. The trait for 'male-pattern baldness' is a recessive trait encoded for by "b". Nonbalding is encoded for by a dominant allele encoded for by the letter "B". A street survey conducted by ‘The Hair Club for Men’ found that out of 1000 men, 360 had male pattern baldness, the other 480 who did not and were heterozygous, and 160 who did not and were homozygous for a full head of hair. a. What are the ratios of phenotypes for ‘bald’ and ‘haired’ in this population? b. Using this ratio information, calculate the allele frequencies for B and b. c. What are the expected frequencies of homozygous and heterozygous genotypes in the population? 6. One (1) in 1700 newborns of Caucasian genetic background in the U.S. have cystic fibrosis. ‘C’ is the allele dominant over the recessive ‘c’ allele that causes a structural change in the cystic fibrosis transmembrane conductance regulator (CFTR) Cl- channel that causes cystic fibrosis. Individuals must be homozygous for the recessive allele to have cystic fibrosis. a. Based on the information above, what percent of the above population has cystic fibrosis (cc or q2)? b. Assuming that this genetic locus for the CFTR channel is under HardyWeinberg Equilibrium, how many newborns would be expected to have cystic fibrosis if 10,000 babies are born into the population? c. Again, assuming Hardy-Weinberg Equilibrium, how many of that group of 10,000 new babies would be heterozygous Cc genotype? 7. A population of jackrabbits has both brown fur (the dominant phenotype) or grey fur (the recessive phenotype) individuals. Brown jackrabbits have the genotype BB or Bb. Grey rabbits have the genotype bb. This population is studied by you for your Senior Project, and you observe that the frequency of the BB genotype is 0.35. a. What is the expected frequency of heterozygous jackrabbits in this population, if the population is under Hardy-Weinberg Equilibrium? b. Another Cal Poly student also studies this same population for their Senior Project in 2030. That student records the fur color for 324 jackrabbits in the population and observes that 27 of those jackrabbits are grey. Is this genetic locus for fur color under Hardy-Weinberg Equilibrium? c. Assuming that this genetic locus is under Hardy-Weinberg Equilibrium, how many jackrabbits of those 324 observed in 2030 should have been brown in color assuming that the frequencies you observed in your senior project were correct? 8. In humans, ABO blood types are determined by allelic composition at the ‘I’ genetic locus. The IA "allele" for ABO blood groups actually consists of two subtypes (IA1 and IA2), with both being considered "IA". In western European populations, about ¾ of IA alleles are IA1, leaving only ¼ as IA2 (Cavalli-Sforza and Edwards, 1967). Assuming this gene locus is under Hardy-Weinberg Equilibrium, calculate the following: a. What would be the expected proportions of IA1IA1 and IA2IA2 genotypes among IAIA individuals in this population? b. In a group of 1,200 IAIA individuals, how many individuals would be expected to have the IA1IA2 genotype?