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Title: How would you construct this restriction map of a plasmid? Post by: smitty2 on Oct 23, 2012 A bacterial plasmid is 100 kb in length. The plasmid DNA was digested to completion with two restriction enzymes in three separate treatments: EcoRI, HaeIII, and EcoRI + HaeIII (double digest). The fragments were then separated with electrophoresis.
EcoRI: 70, 30 HaeIII: 60, 40 EcoRI + HaeIII: 10, 20, 30, 40 Construct a labeled diagram of the restriction map of the plasmid. Thank you SO much! Title: How would you construct this restriction map of a plasmid? Post by: nursinglife on Oct 23, 2012 I love these puzzles (yes, that makes me a nerd - so what).
First, draw a circle. You know that EcoRI cuts two times. So draw a small crossline at 12 o'clock and a line at 8 o'clock. Those are your EcoRI cuts, and your 70 and 30 kb fragments. You also know that HaeIII cuts two times. To know where it cuts, look at the double digest numbers. The double digest tells you that the 30 kb fragment of EcoRI is NOT cut by HaeIII, it is still there. Also, the 40 kb HaeIII fragment is NOT cut by EcoRI. However, the 70 kb EcoRI fragment is cut into 10, 40, 20 kb by HaeIII. The 60 kb HaeIII fragment is cut by EcoRI into 10, 20, and 30 kb. So now you can draw the map. EcoRI at 12 and 8 o'clock. HaeIII at 1.30 and 5 o'clock. I hope this is to scale. The fragment between 12 and 1.30 is the 10 kb, then the 40 kb till 5 o clock, then the 20, then the 30. I hope it is clear. I wish you could see my little drawing here.... |