1. Positive assortative mating results when a. mating pairs are phenotypically different from each other. b. mating pairs are phenotypically alike. c. most matings are the result of outbreeding. d. phenotype is not a criteria in mate selection. 2. Observation of several generations of an inbred population will demonstrate that a. genotypic frequencies can vary while allelic frequencies remain unchanged. b. allelic frequencies can vary while genotypic frequencies remain unchanged. c. no substantial changes occur in genotypic frequencies within an inbred population. d. the average heterozygosity of an inbred population does not change. 3. The offspring of two unrelated parents are likely to be homozygous for a particular trait by descent. 4. In a completely inbred population, the inbreeding coefficient is closest to a. 0. b. 0.5. c. 0.75. d. 1. 5. Children from consanguineous marriages are an example of __________. 6. In a population, a rare recessive metabolic disease is found in 2 of 24,000 individuals studied. What is the estimated frequency of carriers of this disease? a. 0.009 b. 0.020 c. 0.065 d. 0.991 7. In a given population, the frequency of a recessive allele is 0.3. The frequency of the dominant allele is a. 0.1. b. 0.3. c. 0.5. d. 0.7. 8. In a large outbred population, the inbreeding coefficient is closest to a. 0. b. 0.5. c. 0.75. d. 1. --- 9. In a human population, the heterozygosities found at seven different loci are: 0.4, 0.1, 0.0, 0.6, 0.3, 0.0, 0.2. The proportion of polymorphic loci for this population is a. 0.229. b. 0.372. c. 0.481. d. 0.500. 10. For a particular genetic locus, the frequency of the allele that appears most often phenotypically is 0.55. This locus is a. polymorphic. b. pleiomorphic. c. epistatic. d. monomorphic. 11. The reduction in heterozygosity in a self-fertilizing population occurs slowly and can be observed only after many generations. 12. For a locus with five alleles, the allelic frequencies are represented as p, q, r, s, and t. The Hardy-Weinberg heterozygosity can be expressed as a. p2 + q2 + r2 + s2 + t2. b. 1 - 2pq + 2pr + 2ps + 2pt. c. 1 - p2 + q2 + r2 + s2 + t2. d. 2pq + 2pr + 2ps + 2pt. 13. Plants and invertebrates show the highest levels of genetic variation. 14. Sickle-cell disease is a human genetic disorder that shows a. a higher than average frequency of occurrence in individuals of African descent. b. a lower than average frequency of occurrence in Afro-American populations. c. lethality in the heterozygous state. d. selective advantage to homozygotes with the disease. 15. In a small population, __________ __________ can cause a large change in allelic frequencies for a number of traits. 16. Darwin's ship was named the a. H.M.S. Cocker Spaniel. b. H.M.S. Beagle. c. H.M.S. Boxer. d. H.M.S. Great Dane. 17. What is the difference between inbreeding and outbreeding? 18. What is the effect of genetic drift on small populations? --- 19. For a locus in an inbred population a. the frequency of heterozygotes is increased. b. the frequency of heterozygotes is equal to the frequency of homozygotes. c. the frequency of heterozygotes is reduced. d. the frequency of homozygotes is reduced. 20. Mathematically illustrate how inbreeding leads to a high frequency of homozygotes in a population. 21. A chi-square value of 265.3 with 1 degree of freedom would indicate that a. the observed and expected values were consistent. b. the data is statistically insignificant. c. the data supporting the original hypothesis is correct. d. the data is statistically significant. 22. The __________ __________ represents the genetic makeup of a population. 23. A gene that has two or more alleles seen phenotypically on a frequent basis is __________. 24. In a large population, the effect of genetic drift is negligible. 25. After one generation, a negative change in the allelic frequency of a recessive allele is due to selection for the recessive allele. 26. Inbreeding cannot in itself cause a change in allelic frequencies within a population. 27. Sickle-cell disease has a relatively high frequency for a disease allele because a. it is an autosomal dominant disease. b. infection with malaria predisposes an individual to sickle-cell disease. c. homozygotes with malaria have a selective advantage over heterozygous individuals. d. heterozygotes with malaria have a selective advantage over homozygous individuals. 28. An inbreeding coefficient of 1 in a population of self-fertilizing plants means that most of the individuals in the population do self-fertilize. 29. A study of a population of cockroaches has shown that the average heterozygosity for 85 different loci is 0.12. This indicates that a. 12% of the cockroaches in the population will be heterozygous for all 85 traits. b. the frequency of a recessive allele appearing at any given loci is 12%. c. 12% of the loci in a cockroach are heterozygous. d. most of the loci are monomorphic. --- 30. An example of a trait affecting assortative mating would be a. height. b. hair color. c. eye color. d. All of these choices are true. 31. When the inbreeding coefficient for a population is a positive number, the population a. has more heterozygotes than homozygotes. b. has more homozygotes than heterozygotes. c. has an equal number of heterozygotes and homozygotes. d. will have no homozygotes. 32. The Hardy-Weinberg principle shows that for all loci in a population, the frequency of heterozygotes will exceed the frequency of homozygotes. 33. Natural selection can have which effect on a population? a. maintenance of two or more alleles at a locus b. reduce homozygosity for favored alleles c. increase genetic variation in the population d. increase heterozygosity for favored alleles 34. In a population, if the initial frequencies of two alleles at a locus are 0.2 and 0.8, respectively, after 10 generations the frequency of heterozygotes will be a. 0.20. b. 0.35. c. 0.50. d. 0.75. 35. In a population of goats, two alleles affect hiar color: Brown (B1) and blond (B2). Homozygous individuals have either brown (B1B1) or blond (B2B2) hair; heterozygous individuals have grey (B1B2) hair. The population is 70% brown, 10% grey, and 20% blond. a. What is the frequency of the B1 and B2 alleles? b. What is the expected frequency of brown, blond, and grey-haired goats, if the population were breeding randomly? c. How would you tell if the difference between what you observed and what you expected was significant? d. Assuming that the difference was significant, what would cause the genotypic frequencies to differ from those that were expected? In many populations, P, H, and Q are not as expected in the Hardy-Weinberg equilibrium. Describe at least two factors that can alter the values for P, H, and Q. --- 36. The initial frequency of a particular allele in a population is 0.4. The probability that this allele will become fixed is a. 0. b. 0.4. c. 0.6. d. 1.0. 37. The most extreme example of inbreeding in a population is __________. 38. Hardy and Weinberg showed that, for any given gene a. there is usually a binomial relationship between allelic frequencies and genotypic frequencies. b. there is usually a binomial relationship between genotypic and phenotypic frequencies. c. heterozygotes occur twice as frequently as homozygotes. d. the allelic frequencies of male and female gametes are equal. 39. When an allele at a locus has a frequency equal to 1.0, a. the amount of heterozygosity at that locus is high. b. the amount of homozygosity at that locus is low. c. the amount of heterozygosity at that locus is low. d. random mating has occurred. 40. The mean fitness of a population refers to the ability of a population to a. survive natural disasters. b. change genotypically over time. c. select against homozygosity at any given allele. d. pass on its alleles. 41. In a large population, a substantial change in allelic frequency would probably be due to a. genetic drift. b. inbreeding. c. gene flow. d. All of these choices are true. 42. An allele that causes a rare recessive disease in humans when in the homozygous state has a relative fitness of 0.72. The selection coefficient for the homozygous recessive genotype is a. 0.16. b. 0.28. c. 0.56. d. 0.72. 43. In the case of sickle-cell disease, two alleles are maintained in a population because a. homozygotes are more viable in areas where malaria is endemic. b. heterozygotes are more fit than homozygotes. c. heterozygotes are less fit than homozygotes. d. the change in allelic frequency due to selection is negligible. --- 44. The extent of gene flow between two populations can be determined by a. calculating the selection coefficient for each population. b. measuring the rate of loss of heterozygosity for both populations. c. measuring the amount of admixture from the populations. d. All of these choices are true. 45. Polymorphism is limited to a small number of loci in very specialized populations. 46. If the initial frequency of a given allele is 0.1, is it more likely to become fixed, or lost, from a population, assuming that there is no selection? 47. Which of the following represents a population? a. all of the different species of birds living in a rain forest in Africa b. all of the parakeets living in a particular rain forest in Africa in 1987 c. all of the goldfish that have lived in a particular pond in Maine since 1980 d. all of the palomino horses bred in the United States in 1988 48. When a locus contains multiple alleles, the allelic frequencies for that locus cannot be determined by using the Hardy-Weinberg rule. 49. What effect will gene flow eventually have on a large population if the frequency of a recessive allele is 0.2 and the allelic frequency in migrants is 0.6? 50. Polyacrylamide gel electrophoresis of the beta-globin gene products from sickle-cell carriers shows a. one band, smaller than normal beta-globin. b. one band, larger than normal beta-globin. c. two bands, representing proteins synthesized from each allele. d. two bands, representing proteins synthesized from two different genes. 51. In a population of 100 people, 30 are homozygous dominant for a given allele, 50 are heterozygous, and 20 are homozygous recessive. What is the frequency of the dominant allele in this population? a. 0.33 b. 0.55 c. 0.65 d. 0.71 52. In a very small population, a new neutral mutation is likely to become fixed. 53. What effect does inbreeding depression have on the mean fitness of a population? --- 54. The incidence of sickle-cell disease has decreased in populations of Afro-Americans relative to African populations because a. heterozygotes do not have a selective advantage in the United States. b. the homozygous state is lethal. c. the homozygous state is conditionally lethal in the United States. d. American populations are more inbred. 55. Nuclear DNA is widely used to aid in the determination of phylogenetic relationships. 56. Which of the following genes is known to exist in multiple copies on a chromosome? a. the cytochrome c gene b. the alcohol dehydrogenase gene c. genes that encode immunoglobulins d. the cystic fibrosis gene 57. Populations of endangered species, when kept in captivity, show an increase in mean fitness over time. 58. Land race represents the struggle between two species for colonization of a certain habitat. 59. The relative fitness of a recessive disease allele is found to be 0.65. If the mutation rate for the gene is one per million, the expected frequency of the disease allele in an otherwise normal population is a. 0.0017. b. 0.0065. c. one per million. d. 2.9 per million. 60. Environmental pollutants increase the frequency of disease in a population by increasing the __________ __________. 61. Antibiotic-resistant strains of bacteria have become prevalent because a. antibiotic resistance is expressed in heterozygotes. b. bacteria are not affected by antibiotics. c. resistance to antibiotics is often carried on a plasmid. d. bacteria are haploid so the resistance gene is expressed when present on the chromosome. 62. How is pesticide resistance generated in a population? 63. Alleles that are neutral are not expressed in homozygous individuals. 64. What conditions increase the spread of pesticide resistance through a population? --- 65. Establishment of pesticide resistance in an insect population is dependent upon the a. initial frequency of the mutant allele. b. level of dominance of the mutant allele. c. selective advantage of the mutant allele. d. All of these choices are true. 66. In a population of 100 diploid organisms, a neutral mutation arises in an otherwise homozygous locus. The initial frequency of the mutant allele is a. 0.005. b. 0.010. c. 0.050. d. 0.100. 67. For certain recessive diseases, improved medical care can decrease the a. relative fitness of the disease. b. selective disadvantage of the disease. c. mutation rate associated with the disease. d. equilibrium allelic frequency of the disease allele. 68. A high forward mutation rate will __________ the frequency of a disease allele in a population. 69. The high incidence of Ellis-van Crevald syndrome in Amish populations is primarily the result of __________ __________. 70. The neutrality theory is based primarily on the combined effects of a. genetic drift and mutations. b. genetic drift and inbreeding. c. gene flow and inbreeding. d. gene flow and mutations. 71. The mean fitness of an inbred population is likely to decrease over time. 72. Artificial selection can be used to increase the incidence of a favorable trait in a population. 73. Which ethnic group shows a higher than average incidence of the Tay-Sachs allele? a. American b. Hawaiian c. Israeli d. African 74. How are recessive disease alleles maintained in a normal healthy human population? --- 75. A high proportion of consanguinity in a population can result in a. a high rate of mutation for certain genes. b. an increase in gene flow. c. a high incidence of genetic diseases. d. All of these choices are true. 76. In captive populations, loss of genetic variation is primarily due to a. mutation. b. genetic drift. c. gene flow. d. neutrality. 77. Mitochondrial DNA is maternally inherited and shows only a low frequency of genetic exchange. 78. When different alleles appear to have no selective advantage or disadvantage over each other, they are a. fixed. b. orphan. c. neutral. d. conserved. 79. In a population of Drosophila, the frequency of the Adhf allele has been shown to increase when alcohol is present in the environment. The Adhf allele must be influenced by a. neutrality. b. mutation. c. inbreeding. d. selection. 80. Pesticide resistance spreads quickly within species that are preadapted and have a high gene flow. 81. Genetic counseling may be useful in lowering the frequency of which of the following diseases in a population? a. Legionnaire's disease b. tuberculosis c. cystic fibrosis d. All of these choices are true. 82. At a locus with multiple alleles, __________ will increase the number of alleles, and __________ will decrease it. 83. Which of the following traits would be likely to increase in frequency in a normal population over time? a. a brown-eyed mutant in a blue-eyed population b. an autosomal recessive disease c. pesticide resistance d. All of these choices are true. 84. Genes belonging to a __________ __________ exist as multiple copies on a chromosome. --- 85. Disease alleles such as the one causing cystic fibrosis should eventually be lost from a population due to selection, but are not, because a. the relative fitness of most disease alleles is very high. b. new mutations counterbalance the effect of selection. c. there is no selective disadvantage associated with the homozygous state. d. most disease alleles aren't expressed until adulthood. 86. The frequency of a disease allele in a population can be influenced by a. genetic drift. b. selection. c. gene flow. d. All of these choices are true. 87. How is molecular evolution related to population genetics? 88. Orphan diseases a. occur infrequently in a population. b. cannot be traced by pedigree analysis. c. represent new mutations in somatic cells. d. are found only in African populations. 89. The founder effect is a phenomenon that occurs in populations where a. most of the members are heterozygous at a majority of loci. b. most of the members are descended from a common ancestor. c. there is an unusually high incidence of a recessive disease due to mutation. d. the descendants are largely outbred. 90. When an allele is a recessive lethal, the genotypic and allelic frequencies a. are equal to one another. b. increase over time because of selection. c. are equal to 0 and 1, respectively. d. are equal to the mutation rate. 91. In a population consisting of 100 diploid organisms, a neutral mutation arises in an otherwise homozygous locus. The probability that this new allele will become fixed in the population is a. 0.005. b. 0.010. c. 0.050. d. 0.100. 92. The relatively large amount of molecular variation observed at a locus with multiple alleles is primarily the result of a. genetic drift. b. mutation. c. selection. d. All of these choices are true. --- 93. The molecular clock theory can be used to a. pinpoint the time at which two species diverged. b. determine an organism's circadian rhythm. c. determine the amino acid sequence encoded in a gene. d. study the relationship between mtDNA and nuclear DNA. 94. Individuals sharing a similar type of mtDNA a. are descended from a single male ancestor. b. might have a common female ancestor. c. might be completely different because mtDNA mutates at a high rate. d. The relationship between the individuals can't be determined using mtDNA. 95. The goal of conservation genetics when applied to crop plants such as corn is to a. increase the genetic uniformity of a crop. b. decrease the genetic variation of a crop. c. create one strain of the crop that can replace all others. d. maintain genetic variation in a crop. 96. The relative fitness of a recessive disease allele is found to be 0.65. If the mutation rate for the gene is estimated at one per million, the expected frequency of diseased individuals in an otherwise normal population is a. 0.0002. b. 0.0065. c. one per million. d. 2.9 per million. 97. The mean fitness of an inbred population may decrease over time because a. inbreeding increases the number of homozygous recessive individuals for certain disease alleles. b. members of the population are less likely to be homozygous for the disease allele than heterozygous. c. inbred populations show a high rate of mutation. d. All of these choices are true. 98. Pesticide resistance spreads very quickly in populations with a. a low incidence of gene flow. b. no previous exposure to the pesticide. c. a large population size. d. All of these choices are true. 99. Which of the following would cause an increase in pesticide resistance among insect species? a. planting a number of genetically different, but related crops in one area b. planting a single crop species over a vast area c. spraying crops with different types of pesticides d. planting a number of totally unrelated crops in one area --- 100. Doubling the mutation rate for a given recessive allele in a population will result in a. a two-fold increase in the frequency of the allele. b. a four-fold increase in the frequency of the recessive genotype. c. a two-fold increase in the frequency of the recessive genotype. d. no change in the allelic or genotypic frequencies because selection for the allele will also change. 101. Inbreeding depression refers to a net increase in the mean fitness of a population due to inbreeding. 102. In our Drosophila matings, why did we have to have virgin females for the matings? 103. The Tn10 insertion is now being mapped by a gradient of transmission technique. The donor contains the Tn10 insertion; it is an Hfr, with the point of origin and 42 minutes, with the direction of transfer being counterclockwise. It is a prototroph, and streptomycin sensitive. The recipient has mutations at 44 (his), 48 (gyr), 56 (tyrA) and 62 (serA) minutes. The number of recombinants/ml, obtained after a 2 hour uninterrupted mating, was: his+: 3.5 X 10 gyr+: 2.0 X 10 tyr+: 5.5 X 10 ser+: 2.3 X 10 Using a graphical technigue, map the location of the Tn10 insertion, if the frequency of transfer of tet-resistance was 3.0 X 10. 104. Using Tn10, and using lambda 1098 as a vehicle, describe how you would isolate mutants of E. coli that are auxotrophic for thymine. NOTE: Thy- mutants of E. coli are resistant to the drug trimethoprim. 105. Describe how you would clone the thyA gene, using the mini-mu-d vector that we used in class, pEG5005. Alternatively, describe how you would clone the gene using conventional (in vitro) cloning techniques. --- 106. Meiosis in Ascaris megalocephala: In answering the following questions, N indicates the haploid number of chromosomes, C indicates the amount of DNA present in a cell after mitosis. In Ascaris, 2N=4. a. How is fertilization in Ascaris unusual, compared to what occurs in other diploid organisms? b. Define polar body, and distinguish between the first and second polar body, in terms of number of chromosomes and amount of DNA. c. What are pronuclei? 107. You have discovered a new pathogen, Salmonella wilkilus, that has been killing the grandparents of college students during final exams. You have found that the most virulent strains are prototrophs, while milder strains are all auxotrophs for at least one amino acid. You wish to use Tn10 mutagenesis to produce amino acid auxotrophs. Describe how you would do this. (You do not have to go into detail about the Tn10 mutagenesis; just tell how you'd find the auxotrophs). HINT: In the lab, S. wilkilus is sensitive to ampicillin, which only kills growing cells. --- 108. An E. coli strain is resistant to kanamycin. It harbors a plasmid. How would you show that the gene for kanamycin resistance is found on the plasmid? NOTE: The plasmid is NOT capable of conjugation. a. The Tn10 derivative was found on a lambda phage, strain 1098. What characteristics made it useful as a vehicle for delivering Tn10? In particular, why was it unlikely that the tet-resistant colonies were the result of lambda integrating into the host chromosome? b. In selecting recombinants for mapping, care must be taken so that only recombinants are able to grow on a plate. In our experiment, what component of the selection plates (or lack thereof) prevented non-recombinants from growing, either donor or recipient? c. In the cloning experiment, the donor was always a mu lysogen. Why was this so? d. Also in the cloning experiment, why could we assume that, if a recipient had become kanamycin resistant, that it contained the mini-mu-d phage as a plasmid? Why wouldn't it be found inserted into the chromosome? e. In isolating plasmids, what property of plasmids allows the technique that we used to separate the plasmid DNA from the chromosomal DNA? f. In the in vivo cloning experiment, what would have happened if we had selected only for the cloned gene, and not also for kanamycin? Would all of the colonies also have been kanamycin resistant? Why or why not? 109. Using C to indicate the amount of DNA, and N to indicate the number of chromosomes, answer the following questions (2N = the number of chromosomes in a somatic cell; 2C = amount of DNA in a somatic cell immediately after mitosis) N C a. Somatic cell just before mitosis b. Oogonium just before meiosis c. Primary oocyte after telophase I d. Newly formed sperm or egg e. Newly fertilized Ascaris oogonium --- 110. MENDELIAN GENETICS OF DROSOPHILA In a genetic cross, true-breeding female flies with sepia eyes and normal wings were crossed with true-breeding males with normal eyes and vestigial wings. The F1 generation produced all wild-type flies. a. Using se and se+ as symbols for sepia and wild-type eyes, and vg and vg+ as symbols for vestigial wings, indicate the genotypes of the parental and F1 generation flies. b. A count of 200 F2 generation flies produced the following results: 120 wild-type 35 sepia eyes, normal wings 40 normal eyes, vestigial wings 5 sepia eyes, vestigial wings 1. What are the expected results for the F2 generation? 2. Using the expected results and your Chi-square table, determine the probability of these results occurring by chance; is the data consistent with the hypothesis that these traits are inherited in a Mendelian fashion? 111. What is one major difference between mitosis in plants and in animals? ---