Restriction mapping of a linear piece of DNA reveals the following EcoRI restric
ID: 3166185 • Letter: R
Question
Restriction mapping of a linear piece of DNA reveals the following EcoRI restriction sites. EcoRI site 1 EcoRI site 2 2 kb 4 kb 5 kb In each of the scenarios described below, DNA is cut by EcoRI and the resulting fragments are separated by gel electrophoresis. The gel image is pictured on the right A B C D E 11 kb Match each of the scenarios to the lane on the gel that would result after digestion and gel electrophoresis 4 kb 3.5 kb 2 kb Continued below. Digestion is performed on the linear DNA as shown above A mutation that alters EcoRI site 1 occurs in this piece of DNA.Explanation / Answer
1) Two fragments will be produced when a linear DNA is cut at one ECOR1 site. When two sites are present, three fragments should be produced. These will be of sizes 2 Kb, 4Kb and 5 Kb. Lane C shows three bands of 2Kb, 4Kb and 5Kb. Hence, it shows the digestion of the linear DNA.
Digestion performed of linear DNA is shown in C.
2) Mutation in ECOR1 site 1 will cause no cleavage at site 1. Hence, there will be two fragment seen on gel after digestion: 6Kb (2+4Kb) and 5 Kb. Lane A shows two bands of 6 Kb and 5 Kb.
Mutation that alters ECOR1 site 1 occurs in this piece of DNA: Lane A.
3) Mutation in both ECOR1 site will lead to no cleavage of DNA. Hence, a single band of 11 Kb (2+4+5 kb) will be seen. Lane B has a single fragment of 11 Kb.
Mutation in both ECOR1 and 2: Lane B.
4) Insertion of 1000 bp between the ECOR1 sites 1 and 2, will increased the length of fragment 4 Kb by 1 Kb. Hence, there will only be two fragment seen on gel: 5 Kb and 2 Kb. The 5 Kb fragment will have two fragment: one of the increased 1000 bp region between ECOR1 sites and the second of the fragment after ECORI site 2. Such fragments are seen in lane E, which is showing increased amount of band 5Kb
Insertion of 1000 bp: Lane E.
5) When 500 bp is deleted between the two ECOR1 sites, than the size of the middle fragment decreases to 3.5 Kb (instead of 4Kb). Hence, 3 fragments of 2 Kb, 3.5 Kb and 5Kb are obtained. Lane D shows such three fragments.
Deletion of 500 bp between two restriction sites: Lane D
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