percentage of cells that are donor strR mtl strs mtl strR mt

percentage of cells that are

donor

strR mtl-

strs mtl+

strR mtl+

strR mtl+

4.3

0.40

0.17

strR mtl- and

strs mtl+

2.8

0.85

0.0066

A. What does the first row of the table tell you?

B. What does the second row of the table tell you?

The locations of six deletions have been mapped to a Drosophila chromosome, as shown in the following deletion map. Recessive mutations a-f with visible phenotypes are located in the same region, but their order is not known. Flies that are homozygous for a recessive mutation are crossed to flies with a deletion, and the mutant/deletion progeny are examined to see whether they show the mutant phenotype, or not. In the following table, m indicates that the particular combination appears mutant, and + indicates a wildtype phenotype.

	percentage of cells that are
donor	strR mtl-	strs mtl+	strR mtl+
strR mtl+	4.3	0.40	0.17
strR mtl- and strs mtl+	2.8	0.85	0.0066

oo Sprint F 11:22 PM K Bacteria and phage ll deletio Th at does e table tell you e first row B. What does the second row of the table tell you? The locations of six deletions have been mapped to a Drosophila chromosome, as shown in the following deletion map. Recessive mutations a-fwith visible phenotypes are located in the same region, but their order is not known. Flies that are homozygous for a recessive mutation are crossed to flies with a deletion, and the mutant/deletion progeny are examined to see whether they show the mutant phenotype, or not. In the following table, m indicates that the particular combination appears mutant, and indicates a wildtype phenotype. deletion 3 deletion deletion 6 deletion a b c d e f On the basis of these data, place the genes in their correct locations along the chromosome. Courses Calendar To Do Notifications Messages

Solution

Answer:

A. The first row of the data shows the percentage of str^R mtl^-, str^smtl⁺and str^R mtl⁺cells obtained after transformation of str^smtl^- with donor DNA from strR mtl+cells.

B. The second row of the data shows the percentage of str^R mtl^-, str^smtl⁺ and str^R mtl⁺cells obtained after transformation of str^smtl^- with donor DNA from str^R mtl^- and str^s mtl^+.

a is expressed with deletions 1 and 2. Therefore, it must be located in the overlap of 1 and 2.

b is expressed with deletions 3 and 6. Therefore, it must be located in the overlap of 3 and 6.

c is expressed with deletions 1, 3, 4, and must be in the area overlapped by these three.

d is expressed with deletions 3, 4, 5, 6, and must be in the area overlapped by these 4.

e is expressed with deletions 3, 4, 5, and must be in the area overlapped by these three.

f is expressed with deletion 1 only.

The gene order must be f a c e d b.