10. Ch_5_Extra_Questions_Answers

10. Ch_5_Extra_Questions_Answers - In moths the allele for...

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Unformatted text preview: 11/12/09 In moths, the allele for black body, b, is recessive to the allele for normal body colour, b+. The allele for purple eyes, p, is recessive to that for normal eyes, p+. A doubly heterozygous female is crossed to a purple‐eyed, black‐bodied male, and the following progeny are obtained: 91 completely normal, 9 normal body and purple eyes, 11 black body and normal eyes, and 89 black body and purple eyes. What can you conclude about the linkage relaIonship between these two loci? 1.  2.  3.  4.  5.  They are linked & are 10 m.u. apart. They are linked & are 20 m.u. apart. They are linked & are 90 m.u. apart. They are linked & are 5 m.u. apart. They are unlinked. 3 Later experiments showed that the purple‐eyed, black bodied male used in the preceding quesIon was carrying an addiIonal mutaIon that made it impossible for any crossing over to occur in any of his gametes. How does this affect the answer to the previous quesIon? 1.  Map distances should be doubled. 2.  Map distances should be halved. 3.  Map distances might not be right, but too hard to tell. 4.  It has no effect on the answer 4 1 11/12/09 The r & s genes are linked & are 10 m.u. apart. True‐breeding parents, RRss & rrSS are crossed to form the F1. If the F1 is test‐ crossed, what proporIon of progeny will be Rrss? 1.  2.  3.  4.  5.  5% 10% 20% 40% 45% 5 The C and D gene are known to be 20 map units apart. In a cross between CCDD x ccdd, what proporIon of F2 progeny (formed by interbreeding the F1) will have the ccdd genotype? 1.  2.  3.  4.  5.  0.4 0.25 0.2 0.16 0.8 6 2 11/12/09 The following cross is performed.: aaBB x AAbb. Which of the following statements is (are) true? 1.  2.  3.  4.  5.  If the loci are closely linked, the F1 would produce AB gametes as o_en as Ab gametes. If the loci are closely linked, the F1 would have a different phenotypic distribuIon than it would if they weren’t linked. If the loci are closely linked, the F2 would have a different phenotypic distribuIon than it would if they weren’t linked. All of the above are correct. None of the above are correct. Once you eliminate some answers to a question, look through the answers and eliminate any that say ‘all of the above’. 7 2 X‐linked genes, E & F are 30 m.u. apart. A cross is performed between a homozygous wild‐type female & a male with a mutant phenotype for both genes. If the F1 female is then crossed with the F1 male, what proporIon of FEMALES will be homozygous wild‐type for both genes in the F2. 1.  2.  3.  4.  5.  0.5 0.35 0.25 0.45 0.65 8 3 11/12/09 An F1 individual heterozygous for three genes, XxYyZz, is testcrossed. The most abundant classes are xxYyzz, and XxyyZz, while the rarest classes are XxYyzz and xxyyZz. Which gene is in the middle? 1.  2.  3.  4.  X Y Z Can’t be determined. 9 Three loci are known to be linked. The D locus is 20 map units from the E locus and the E locus is 20 map units from the F locus. The order of the loci is DEF. The cross DDEEFF x ddeeff is made, and the progeny from that cross are test crossed. A_er all of the progeny of the test cross have been scored for phenotype, it is discovered that 2% are D‐ eeF‐ and 2% are ddE‐ffin phenotype. Based on these data, what is the coefficient of coincidence in the region? 1.  2.  3.  4.  0.5 0 1 None of the above, but it can be calculated with these data. 5.  It can’t be calculated from these data. 10 4 11/12/09 In Drosophila, the genes b,c, and sp are linked in the order given. bc = 30 m.u. and csp = 20 m.u. These intervals exhibit 90% interference. How many double crossovers would be recovered (would happen) out of 1000 progeny resulIng from a 3‐point cross involving these three genes? 1.  2.  3.  4.  5.  3 6 54 60 600 11 A cross is made between 2 different inbred Drosophila lines, each with a single mutaIon for eye colour. The F1 all have wild‐type red eyes. When the F1 is back‐crossed to a homozygote for both mutaIons, the resulIng progeny are 1/10 wild type, and 9/10 mutant phenotypes. Which of the following is true of these genes? 1.  2.  3.  4.  5.  MutaIons in different genes; 20 m.u. apart. MutaIons in same gene; 10 m.u. apart. MutaIons in same gene; 20 m.u. apart. MutaIons in different genes; 10 m.u. apart. MutaIons in same gene; 5 m.u. apart. This question involves complementation. 12 5 11/12/09 F1 w+y+/wy wy/Y red eyes, brown body white eyes, yellow body Please note – there was an error in this question as previously posted. What fracIon of male progeny will have white eyes, yellow body if the proporIon of recombinants is 1%? 1.  2.  3.  4.  5.  1/2 0.5% 49.5% 99% 1% 13 F1 w+y+/wy wy/Y red eyes, brown body white eyes, yellow body Please note – there was an error in this question as previously posted. What fracIon of female progeny will have white eyes, brown body if the proporIon of recombinants is 1%? 1.  2.  3.  4.  5.  1/2 0.5% 49.5% 99% 1% 14 6 11/12/09 Blue flower, long stem, x white flower, short stem, wrinkled seed round seed F1 blue flower, long stem, x white flower, short stem, round seed wrinkled seed Which gene is in the middle? a)  Flower colour b)  Stem length c)  Seed shape 112 blue, long, round 340 blue, long, wrinkled 8 blue, short, round 32 blue, short, wrinkled 37 white, long, round 4 white, long, wrinkled 328 white, short, round 121 white, short, wrinkled 15 Chromosome 4 of Drosophila experiences no recombinaIon. Which of the following is NOT correct? 1.  All the genes on this chromosome must be very close together in base pairs of DNA. 2.  EsImated map distances between genes should always give 0 m.u. 3.  If A & B are both on chromosome 4, no AB/ab F1 will produce only 2 kinds of gametes. 4.  All genes on this chrom IGNORE THIS SLIDE!!!! 16 7 11/12/09 The r & s genes are linked & are 30 m.u. apart. Truebreeding parents, RRss & rrSS are crossed to form the F1. If the F1 is test-crossed, what proportion of progeny will be Rrss? 1.  2.  3.  4.  5.  15% 30% 35% 45% 60% 17 The C and D gene are known to be 20 map units apart. In a cross between CCDD x ccdd, what proportion of F2 progeny (formed by interbreeding the F1) will have the ccdd genotype? 1.  2.  3.  4.  5.  0.4 0.25 0.2 0.16 0.8 18 8 11/12/09 Strain met+ lys+ is crossed with met lys. Assign genotypes to the resulting spores. How far apart are these two genes? Type 1 ascus (89) 2 spores grow on any media 2 spores grow only on met + lys Type 2 ascus (11) 1 spore grows on any media 1 spore grows on lys & met + lys 1 spore grows on met & met + lys 1 spore grows only on met + lys 1.  2.  3.  4.  0.5 m.u. 1 m.u. 11 m.u. 5.5 m.u. 19 A yeast that grows on minimal media is crossed with a yeast that only grows in the presence of his & leu. Assuming these genes are tightly linked, which of the following is true of the unordered tetrads formed by the F1 progeny? 1.  The most common tetrads will be those with 2 spores that grow on minimal media & 2 that grow only on his+leu. 2.  The rarest tetrads will be those with 2 spores that grow only on leu & his+leu, & 2 spores that grow only on his & his+leu. 3.  The number of PD exceeds the number of NPD 4.  #1 & 3 are correct, but not #2. 5.  #1-3 are correct. 20 9 11/12/09 A yeast spore is found to have the following growth results: minimal media = no growth “ “ + met = no growth “ “ + leu = no growth “ “ + arg = no growth “ “ + met & +leu = no growth “ “ + met & +arg = growth “ “ + leu & arg = no growth “ “ + met & +leu & + arg = growth What is the genotype of the yeast spore? 1.  met LEU arg 2.  MET LEU ARG 3.  met leu arg 4.  MET leu arg 5.  MET LEU arg 21 Which of the following is true of unordered tetrad analysis with 2 genes? 1.  If the genes are linked, the # of PD is expected to be slightly greater than the # of NPD. If the genes are linked, the # of PD is much greater than the # of NPD. If the genes are unlinked, the proportion of tetratypes reflects the distance of the genes from their centromeres. 1&3 2&3 22 2.  3.  4.  5.  10 ...
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This note was uploaded on 01/10/2010 for the course BIOLOGY biol2040 taught by Professor Tamarakelly during the Fall '09 term at York University.

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