Question

V R R V & EcoR1 8 , EcoR1, R & & PST1 PST1 Size Markers R & EcoR1 4 Calf Liver Calf & EcoR1 Liver 7 6 5 3 2 1 Wells 16mm Base Pairs 6650 4973 38mm - 45mm 55mm 59 mm 55mm 3148 2396 55mm - 68mm 76mm 1585 80mm 692 104mm

What happens when vector DNA is digested with EcoRI and what does this tell you about the number and distribution of EcoRI sites in the vector?

How big (in base pairs) is (are ) the fragments generated by digesting the vector with EcoRI?

Answer 1

EcoR1 is a restriction endonuclease that identifies the pallindromic sequence GTTAAC and cleaves double stranded DNA . First we will calculate the fragment size based on DNA marker in the image

There is a linear relation and negative correlation between Log10 (DNA length) and distance travelled from the well (in mm). A standard graph is ploted where, Log10 (marker DNA length) is on Y-axis and distance travelled (in mm) is on X- axis. Based on the standard plot the size of vector is approximately, 3664bp and Ecor1 digest has two bands is approximately 3664bp and 1785bp.

The lighter band of 3664bp represents the uncut vector

and 1785bp represents two bands of almost equal size (1785 x 2 = 3570)

Therefore, there are two restriction site on the vector, which coverted a circular vector in two linear fragments.