Answer all parts! Thanks! 3. In the cross H anc arg\' eoex F-gre arg gee, the fi

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Answer all parts! Thanks!

3. In the cross H anc arg' eoex F-gre arg gee, the first gene, are too close together to infer their order by timed mating. After mating, bacteria are plated on medium containing Ery, Arg, and Arg, 300 bacterial colonies are obtained What are the 4 possible genotypes of bacteria that can grow on this a. plate? Write them in the table below (1 pt) Geno # of Colonies Total 300 b. but The 300 colonies are replica-plated onto a plate that contains does not contain the nutrients Arg or Aro, 252 of the colonies grow What genotype(s) are these colonies? Based on this information, start to fill in column 2 of the above table. (1 pt) When the same 300 colonies are replica-plated onto a plate that contains Ery and Arg, 253 colonies grow. What genotype(s) are these colonies? Based on this information, continue to fill in column 2 of the above table. (1 pt) c. d. When the same 300 colonies are replica-plated onto a plate that contains Ery, and Ar, 279 colonies grow. What genotype(s) are these colonies? Based on this information, continue to fill in column 2 of the above table. (1 pt) e. Based on the information in b-d, how many colonies of the remaining genotype exist? (1 pt) f. Based on the data from a-d, determine the gene order and genetic distances of gre are and exx (2 pt)

Explanation / Answer

As 263 colonies grow when only erythromycin is added, so these must be arg+ aro+ eryr. Therfore, the remaining 37 cultures are mutant for one or both genes. One additional colony grew if arginine was also added to the medium i.e. 264 – 263=1. Of these, 27 are aro– (290 – 263 = 27). The genotypes and their frequencies are :

263 = eryr arg+ aro+ ; 27 = eryr arg+ aro– ; 1= eryr arg– aro+ ; 9 = eryr arg– aro–

Recombination in the aro–arg region is represented by two genotypes: aro+ arg– and aro– arg+. The frequency of recombination is: 100%(1 + 27)/300 = 9.3% (m.u.)

Recombination in the ery–arg region is represented by two genotypes: aro+ arg– and aro– arg–. The frequency of recombination is: 100%(1 + 9)/300 = 3.3% (m.u.)

Recombination in the ery–aro region is represented by three genotypes: arg+ aro–, arg– aro–, and arg– aro+. The frequency of recombination is: 100%(27 + 9 + 2 )/300 = 12.6% (m.u.)

Therefore,the ratio is 28:10, or 2.8:1.0

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