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Unformatted text preview: 8/19/08 Clicker Question 91 If a heterozygous parent (AB/ab) is test crossed to a homozygous recessive (ab/ab), what will the progeny phenotypic ratio be if genes A and B are completely linked? A. 1AB:1Ab:1aB:1ab B. 9AB:3Ab:3aB:1ab C. 1AB:1ab D. none of the above Clicker Question 92 If genes A and B are linked, what is the maximum percentage of recombinant gametes that can be produced during gametogenesis? A. 0% B. 25% C. 50% D. 75% E. 100% 1 8/19/08 Clicker Question 93 From the cross AB/ab ab/ab, what is the recombination frequency if the progeny numbers are 72 AB/ab, 68 ab/ab, 17 Ab/ab, and 21 aB/ab? A. 0.213 B. 0.271 C. 0.500 D. 0.787 E. cannot be determined Clicker Question 94 Were the genes in the heterozygous parent in repulsion or coupling? [From the cross AB/ab ab/ab, what is the recombination frequency if the progeny numbers are 72 AB/ab, 68 ab/ab, 17 Ab/ab, and 21 aB/ab?] A.coupling B.repulsion C.neither D.both 2 8/19/08 Clicker Question 95 What is the order of the linked genes R, S, and T if the distance between R and S is 22 m.u., the distance between S and T is 8 m.u., and the distance between R and T is 14 m.u.? A. R S T B. S T R C. T R S D. cannot be determined Clicker Question 96 Consider the following threepoint cross: Which of the following is not a possible genotype? (Consider both recombined and nonrecombinant.) A. A_____B_____C D. A_____b_____C a b c a b c B. a_____B_____C a b c C. A_____B_____C A B C E. a_____b_____c a b c A_____B_____C a_____b_____c a b c a b c 3 8/19/08 Clicker Question 97 A threepoint testcross is used to determine the order of three linked genes. The following crossover classes occur: single crossovers, double crossovers, and no crossovers (nonrecombinant). When compared to the nocrossover progeny, what other crossover class needs to be considered in determining gene order? A. the nocrossover class B. the singlecrossover class C. the doublecrossover class D. All classes need to be considered in determining gene order. Clicker Question 98 In a threepoint testcross the nonrecombinant progeny are A+ B+ C+ and a b c. The doublecrossover progeny are A+ B+ c and a b C+. Which locus (A, B, or C) is in the middle? A. A B. B C. C D. Either A or B 4 8/19/08 Clicker Question 99 You calculate an interference of 0.59. What does this number tell you? A. You will not observe 59% of expected double crossovers. B. You will observe 59% double crossovers. C. You will observe 41% double crossovers. D. You will observe 59% of expected double crossovers. Clicker Question 910 Two genes that are 60 map units apart are expected to show _______ recombination. A. no B. 25% C. 30% D. 50% E. 60% 5 ...
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- Summer '08