How to : Restriction Map?

I’ve never had to do this particular type of problem, but I use restriction digests at work to check whether my plasmids are correct.

This is what I would do:

1) Cut out a circle of paper and use that to trace another circle on a sheet of paper.

2)You know the total size of the plasmid is 100 kb since the lengths of the fragments in each lane add up to 100. Make 10 evenly-spaced tick marks around the edges of each circles to divide them into 10-kb sections.

3) Set one tickmark on the traced circle as “0/100” to be your reference mark. Then distances will be calculated as you move clockwise from that tickmark. Label the other marks on this circle by tens till you get back to the 0/100 mark.

4) You know the lengths of the EcoRI fragments are 70 and 30 kb, so put an E by the 0/100 and 70 marks on the traced circle. You can see that if you digested your plasmid with EcoRI (just the bigger circle), you’d split it into a 70-kb piece and a 30-kb piece.

5) On the cutout circle write an H next to one mark and then another H six marks away, so that the cutout circle represents a HaeIII digest that would result in 60-kb and 40-kb pieces.

6) Double digests are just digests with two enzymes in the tube instead of one. That means that your plasmid will be cut wherever there is either an EcoRI site or a HaeIII site.

7) Lay the HaeIII circle on top of the EcoRI circle and look at the positions of the restriction sites. Imagine cutting your plasmid apart at all of the restriction sites simultaneously. Are your HaeIII sites in the correct position relative to the EcoRI sites to give you fragments of 10, 20, 30, and 40 kb? If not, rotate the HaeIII circle one step and check again.

**I tried this with your problem and got multiple positions that would give you double-digested fragments of the desired length. You may need more information to be able to choose precisely one correct configuration. As I said, I’ve never actually done one of these problems, but this method makes sense to me.

Hope that helped some.

What you’re dong is slicing a linear lambdaphage genome with each and every of the enzymes. Draw a at as quickly as line on a bite of paper. the dimensions of the uncut genome is 44972 bp. You next draw hatch marks on the genome on the sires the place each and every of the enzymes cuts. For EcoRI, you will mark the place 21226 bp may well be (approximately midway between the two ends, then yet another mark 5000 bp farther up for the 26104, and so on, and so on. Denote each and every with a E for EcoRI. try this for each enzyme. you additionally can Google lambda EcoRI, HindIII, and so on.