Use of Restriction Enzymes

for Gene Mapping


  


The following simplified example demonstrates how restriction
enzymes can be used to create a physical map of the location of
restriction sites within genes on a strand of DNA.

This example describes an experiment where a single strand of DNA
is analyzed to determine the position of 7 restriction sites, and
the resulting gene fragments are arbitrarily labeled
A, B, C, D, E, F, and G. It is assumed that a
collection of restriction enzymes (abbreviated RE) are
available that can cleave this strand at various locations within
the gene, and that appropriate probes are available to analyze the
fragments obtained from gel electrophoresis. (In practice,
selective probes would be used so that not all fragments would
be detected.  In addition, it is highly unlikely that each fragment
would be the same size.)

 The following results are obtained from a series of experiments.
 The goal is to determine the correct gene fragment sequence.  The
 table below shows the results obtained from a series of gel
 electrophoresis experiments. The DNA section of interest was
 cloned using either virus/bacteria growth or by the PCR.  Samples
 were then cleaved with restriction enzymes to produce DNA fragments.
 These DNA fragments were separated using gel electrophoresis and
 analyzed with specific probes. The gene fragments present in each
 DNA fragment are shown in the table below.


  

    
R.E. #1
    
R.E. #2
    
R.E. #3
    
R.E. #4
  

  

    

      .
.
.
* BDEG
* ACF
.
.
    
    

      * ABDEFG
.
.
.
.
.
* C
    
    

      .
.
.
* BDFG
.
* AC
* E
    
    

      .
.
.
* ACFG
.
* BE
* D
    
  

  

    

      Start of Gel Electrophoresis at top.

      Larger fragments move more slowly
    
  




Enter your answer for the correct gene fragment sequence here:




To see if you are correct, press here:


(If you are correct, your answer will be all Uppercase
   letters.
If you are not, your answer will be all Lowercase
   letters.)


If you would like an explanation, press here:



  


  


Last modified March 12, 1997

Kent State University - Stark Campus

Department of Chemistry

This Page Written and Maintained by Dr. Clarke Earley