Restriction Mapping - Introduction

Introduction
Step 1
Step 2
Step 3
Step 4
Step 5
Step 6
Step 7
Exercise 1
Exercise 2
Reference

A restriction map is a diagram that indicates the relative positions of restriction enzyme sites on a particular DNA sequence. To construct a map the DNA in question is cut with a variey of restriction enzymes both singly and in combination. The resultant fragments are separated by agarose electrophoresis and their sizes (in base pairs) are determined by comparing them with a standard size marker. The process of assembling a map is a somewhat trial and error process in which you construct possible maps, predict the sizes of fragments obtained from this map and compare the predictions with the actual data. The correct map is the one that accounts for all of the bands seen on the gel. Although the process is trial and error there are several steps that will simplify the process.

Description of Images

A typical ethidium bromide stained gel that is seen in lab looks like the image on the far left. However, we have taken the liberty (in order to make the material easier to view and to save on printer ink) to make a simulated gel image which consistently looks like the closest image. This simulated image would represent a chemiluminescent type of gel staining procedure. At the top of each lane is the name(s) of the restriction enzyme(s) used to digest the DNA or the type of size marker used. The box just below the enzyme name represents a shaded lane well from which DNA migration starts. The dark bands are the DNA bands themselves, which migrate from the top of the image to the bottom.

Begin the tutorial