Test Bank for Genetic Analysis: An Integrated Approach, 3rd Edition

Genetic Analysis: An Integrated Approach, 3e (Sanders) Chapter 2 Transmission Genetics 2.1 Multiple-Choice Questions 1) Genetic crosses in which F1 plants heterozygous for a given allele are crossed to generate a 3:1 phenotypic ratio in the F2 generation are known as ________. A) replicate crosses B) reciprocal crosses C) test crosses D) monohybrid crosses E) dihybrid crosses Answer: D Section: 2.2 Skill: Remembering/Understanding LO: S2.2a, S2.2b 2) In peas, the smooth allele is dominant over the wrinkled allele. A plant with round peas was crossed to a plant with wrinkled peas and all of the resulting plants had smooth peas. What are the genotypes of the parents in this cross? A) RR × rr B) RR × Rr C) Rr × rr D) Rr × Rr E) rr × rr Answer: A Section: 2.2 Skill: Applying/Analyzing LO: S2.2c 3) In peas, the yellow allele is dominant over the green allele. A plant with yellow peas was crossed to a plant with green peas. The resulting plants were 50% yellow and 50% green. What are the genotypes of the parents in this cross? A) YY × yy B) YY × Yy C) Yy × yy D) Yy × Yy E) yy × yy Answer: C Section: 2.2 Skill: Applying/Analyzing LO: S2.2c 1 Copyright © 2019 Pearson Education, Inc. 4) What genotypic ratio would you expect to observe among the progeny of a monohybrid cross? A) 1:3 B) 9:3:3:1 C) 1:2:1 D) 1:3:2:1 E) 3:1 Answer: C Section: 2.2 Skill: Applying/Analyzing LO: S2.2b 5) You count 1000 F2 seeds from a monohybrid cross. How many seeds do you expect to display the dominant phenotype? A) 1000 B) 750 C) 500 D) 250 E) 0 Answer: B Section: 2.2 Skill: Applying/Analyzing LO: S2.2b 6) Assuming independent assortment, what phenotypic ratio would you expect to see if an individual with the genotype RrGg is self-crossed? A) 1:3 B) 9:3:3:1 C) 1:2:1 D) 1:3:2:1 E) 3:1 Answer: B Section: 2.3 Skill: Applying/Analyzing LO: S2.3a 2 Copyright © 2019 Pearson Education, Inc. 7) In peas, axial (A) flower position is dominant to terminal (a), tall (L) is dominant to short (l), and yellow (Y) is dominant to green (y). If a plant that is heterozygous for all three traits is allowed to self-fertilize, how many of the offspring would show the dominant phenotype for all three traits? A) 3/64 B) 9/64 C) 27/64 D) 32/64 E) 64/64 Answer: C Section: 2.3 Skill: Applying/Analyzing LO: S2.3d 8) In peas, axial (A) flower position is dominant to terminal (a), and tall (L) is dominant to short (l). If a plant that is heterozygous for both traits is allowed to self-fertilize, how many of the offspring would also be heterozygous for both traits? A) 9/16 B) 1/4 C) 3/16 D) 1/8 E) 1/16 Answer: B Section: 2.3 Skill: Applying/Analyzing LO: S2.3b 9) What phenotypic ratio would you expect as a result of a test cross between two individuals where one that is homozygous recessive for alleles at two independent loci? A) 3:1 B) 1:2:1 C) 1:1:1:1 D) 9:3:3:1 E) 9:4:2:1 Answer: C Section: 2.3 Skill: Applying/Analyzing LO: S2.3a 3 Copyright © 2019 Pearson Education, Inc. 10) If a plant with purple, axial flowers and green, inflated pods is heterozygous for all four genes, how many different types of gametes can it produce? A) 1 B) 4 C) 8 D) 9 E) 16 Answer: E Section: 2.3 Skill: Applying/Analyzing LO: S2.3e 11) In Guinea pigs, short hair (S) is dominant over long hair (s), rough coat (R) is dominant over smooth coat (r), and black hair (B) is dominant over white hair (b). Which of the following individuals could produce these (and only these) four possible gametes: SRb, Srb, sRb, srb. A) SSRRbb B) ssRrBB C) SsRrbb D) SsRrBb E) SSRrBb Answer: C Section: 2.3 Skill: Applying/Analyzing LO: G3, S2.3e 12) The gene L determines hair length in rabbits. The gene B determines hair color. A rabbit with long, black hair is crossed to a rabbit with short, white hair. All the offspring have long, black hair. What are the genotypes of the parents? A) LLBB × llbb B) LlBb × LlBb C) LlBb × llbb D) Llbb × llBb E) Impossible to determine from the information given Answer: A Section: 2.3 Skill: Applying/Analyzing LO: S2.3d 4 Copyright © 2019 Pearson Education, Inc. 13) In rabbits, long hair and black fur are produced by the dominant alleles L and B, which assort independently. The genotype ll produces short hair and the genotype bb produces white fur. A cross between a male with short, black fur and a female with long, white fur produces four offspring with short, black fur, four offspring with long, white fur, four offspring with short, white fur, and four offspring with long, black fur. What are the genotypes of the parents? A) llBB × LLbb B) LlBb × LlBb C) llBb × Llbb D) LLBB × llbb E) Impossible to determine from the information given. Answer: C Section: 2.3 Skill: Applying/Analyzing LO: S2.3d 14) A couple has four children. What is the probability that they have four boys? A) 1/2 B) 1/4 C) 1/8 D) 1/16 E) 1/32 Answer: D Section: 2.4 Skill: Applying/Analyzing LO: G4, S2.4 15) By convention, when an OBSERVED experimental outcome has a probability of occurrence of less than 5% ( 0.05). Therefore, the chance hypothesis that the two genes assort independently cannot be rejected. Section: 2.5 Skill: Applying/Analyzing LO: G2, G3, G4, G9, S2.3b, S2.3c, S2.5 18 Copyright © 2019 Pearson Education, Inc. 6) A geneticist is investigating the inheritance of two autosomal recessive genes in mice, one for obesity (LEP) and another for autism (oprm1). The table below provides the number of offspring observed, for each phenotype, when dihybrid mice are testcrossed: Phenotype Observed(O) Expected (E) wild-type 88 obese 68 autistic 64 obese, autistic 80 O-E (O-E)2 (O-E)2/E ∑ (O-E)2/E= Fill in the table above and determine: a. the chi-square (χ²) value (to the nearest hundredth) for the chance hypothesis that the two genes assort independently b. the degrees of freedom c. whether or not you would reject your chance hypothesis that the two genes assort independently, based on your approximate P value, and the justification for why Answer: Phenotype Observed(O) Expected (E) O-E (O-E)2 (O-E)2/E wild-type 88 75 13 169 2.533 obese 68 75 -7 49 0.653 autistic 64 75 -11 121 1.613 obese, autistic 80 75 5 25 0.333 ∑ (O-E)2/E= 4.85 a. 4.85 b. 3 c. You would fail to reject the chance hypothesis since the observed outcomes have a P value greater than 5% (> 0.05). Therefore, the chance hypothesis that the two genes assort independently cannot be rejected. Section: 2.5 Skill: Applying/Analyzing LO: G2, G3, G4, G9, S2.3a, S2.3c. S2.5 19 Copyright © 2019 Pearson Education, Inc. 7) Tim and Mary are planning to start a familiy. While neither of them have cystic fibrosis, a rare autosomal recessive disease, they are concerned that their children could have the disease since Tim’s father, John, AND Mary’s brother, Ralph both have the disease. a. Draw a pedigree of the inheritance of the cystic fibrosis allele in this family. b. On your pedigree, indicate any individuals that must be carriers. c. What is the probability that Tim will be a carrier for the disease allele? d. What is the probability that Mary will be a carrier for the disease allele? e. What is the probability that Tim and Mary will have a child with the disease? Answer: a. b. c. 1 d. 2/3 e. 1/6 Section: 2.6 Skill: Evaluating/Creating LO: G2, G3, G4, G5, S2.6b, S2.6c S2.6d 20 Copyright © 2019 Pearson Education, Inc.