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In the experiment of Figure 7.1, Lederberg and Tatum could not discern whether
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Genetics: Analysis and Principles
- Using the technique of interrupted mating, five Hfr strains were tested for the sequence in which they transmitted several different genes to an F- strain. Each Hfr strain was found to transmit its genes in a unique sequence, as follows (only the first six genes transmitted were scored). Hfr 1 F O P R S Q Hfr 2 R P O F G Y Hfr 3 Y X W Q S R Hfr 4 W Q S R P O Hfr 5 F G Y X W Q A. For each of the Hfr strains, state which donor-gene marker should be selected in the recipients after conjugation to obtain the highest proportion of recombinants that will be Hfr? Strain 1 Strain 2 Strain 3 Strain 4 Strain 5arrow_forwardThree different Hfr donor strains are mixed with separate samples of an F strain, and the following mapping data are provided from studies of interrupted conjugation: Appearance of genes in F cells Hfr1: Genes b* d* c* f* g* Time* 3 16 27 59 Hfr2: Genes e* f* c* d* b+ Time 6 24 35 46 48 Hfr3: Genes d* c* f* e+ g* Time 4 15 26 44 58 Construct a genetic map for these genes, indicating their order on the bacterial chromosome and the distances between them.arrow_forwardWhen the interrupted mating technique was used with five different strains of Hfr bacteria, the following orders of gene entry and recombination were observed. On the basis of these data, draw a map of the bacterial chromosome. Do the data support the concept of circularity?Hfr Strain Order1 T C H R O2 H R O M B3 M O R H C4 M B A K T5 C T K A Barrow_forward
- Three different Hfr donor strains are mixed with separate samples of an F− strain, and the following mapping data are provided from studies of interrupted conjugation: Appearance of genes in F − cells Hfr1: Genes b+ d+ c+ f+ g+ Time* 3 5 16 27 59 Hfr2: Genes e+ f+ c+ d+ b+ Time 6 24 35 46 48 Hfr3: Genes d+ c+ f+ e+ g+ Time 4 15 26 44 58 Construct a genetic map for these genes, indicating their order on the bacterial chromosome and the distances between them.arrow_forwardThe following two strains of E. coli are crossed with each other: Hfr pan* thi* ala* and F¯pan¯ thi¯ ala¯ It was shown that the pan marker entered last in interrupted conjugation experiments. By spreading the bacteria from these experiments on different selection media, the following results (in number of colonies) were obtained: MM + Gluc IM + Gluc + ala MM + Gluc + thi MM + Gluc + thi + ala 280 281 286 339 Give the number of each phenotypic class and justify your answer. Determine the order of the genes. What are the genetic distances between the different loci? Abbreviations: Gluc: glucose; Ala: alanine; Thi: thiamine; Pan: pantothenic acid.arrow_forwardEight mutant bacteriophage strains cannot lyse a certain type of bacteria that can be lysed by wild-type bacteriophages. The mutant strains were allowed to infect the bacteria in a complementation test. A "+" indicates that lysis occurred with coinfection. A "-" indicates that lysis did not occur. OXWTMAO G K Т Т М А А Q C GKWTMAQC +++++ - - - - - - - + - + - + - - + - - - O +++ - + - - + + A cistron is defined by no complementation in the How many genes are controlling lysis in this bacteriophage? (Use a number not a word in the space) configuration.arrow_forward
- DNA from a strain of Bacillus subtilis with genotype a+ b+ c+ d+ e+ is used to transform a strain with genotype a− b− c− d− e−. Pairs of genes are checked for cotransformation, and the following results are obtained: Pair of genes Cotransformation Pair of genes Cotransformation a+ and b+ No b+ and d+ No a+ and c+ No b+ and e+ Yes a+ and d+ Yes c+ and d+ No a+ and e+ Yes c+ and e+ Yes b+ and c+ Yes d+ and e+ No On the basis of these results, what is the order of the genes on the bacterial chromosome?arrow_forwardDNA from a strain with genotype a+b+c+d+ is used to transform a strain with a genotype a-b-c-d-. Pair of genes are checked for cotransformation and the data was collected. Pair of genes Cotransformation Pair of genes Cotransformation a+b+ Yes c+e+ Yes b+c+ No d+e+ No a+e+ Yes b+e+ No d+c+ Yes b+d+ No d+a+ No a+c+ No Using the data in #7, determine which locus is closest to a. c e b can’t determine from the data What are the methods of genetic material transfer in bacteria? Transformation Transduction Conjugation None of these All of these Along with mutation, which of the following is another way that bacteria acquire antibiotic resistance through horizontal gene transfer? Transformation Transduction Conjugation None of these All of thesearrow_forwardDNA from a strain of bacteria with genotype a+ b+ c+ d+ e+ was isolated and used to transform a strain of bacteria that was a− b− c− d− e−. The transformants were tested for the presence of donated genes. The following genes were cotransformed: a+ and d+ b+ and e+ c+ and d+ c+ and e+ What is the order of genes a, b, c, d, and e on the bacterial chromosome?arrow_forward
- DNA from a strain of Bacillus subtilis with genotype a* b* c* d* e* is used to transform a strain with genotype a b c d e. Pairs of genes are checked for cotransformation, and the following results are obtained: Pair of genes Cotransformation Pair of genes Cotransformatic a* and b* No b* and d* No a* and c* No b* and e* Yes a* and d* Yes c* and d* No a* and e* Yes c* and e* Yes b* and c* Yes d* and e* No On the basis of these results, what is the order of the genes on the bacterial chromosome?arrow_forwardThree different Hfr strains, derived from the same F* strains (H), were mated with F strains auxotrophic for a number of nutritional requirements (trp bio leu azi mal tyr gal ). Matings were interrupted at various intervals and cells were plated on minimal medium supplemented with particular nutrients to test for gene transfer. The following mapping data was obtained: Genes mal Hfr strains leu 25 trp 17 bio azi gal* tyr Hfr H Hfr 1 Hfr 2 Hfr 3 Hfr 4 4 10 10 18 3 9. 16 14 22 15 3 19 19 11 4 8 Draw a circular map of E. coli chromosome. Include distances (in minutes) between genes in your map and label arrowheads to show the origin of transfer for the five Hfr strains.arrow_forwardUsing bacteriophage P22, you performed a threefactor cross in Salmonella typhimurium. The crosswas between an Arg− Leu− His− recipient bacteriumand bacteriophage P22, which was grown on an Arg+Leu+ and His+ strain. You selected for 1000 Arg+transductants and tested them on several selective media by replica plating. You obtained the followingresults:Arg+ Leu− His− 585Arg+ Leu− His+ 300Arg+ Leu+ His+ 114Arg+ Leu+ His− 1a. What are the cotransduction frequencies of argwith either his or leu?b. Is arg closer to his than it is to leu, or is arg closerto leu than it is to his? What are the relative mapdistances?c. Why can you not obtain an accurate cotransductionfrequency for his and leu from the data provided?d. What is the order of the three markers?e. Draw the crossovers that would produce the classwith only one transductant.f. Estimate the proportion of the 4.9 Mb S. typhimuriumgenome that contains these three genes. Assume thatbacteriophage P22 can package the same amountof DNA as the…arrow_forward
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