GE In-Depth GE In-Depth

GE Basics
Locating Genetic Information

Timeline of GE

Recombinant DNA:
How Genes Are Transferred


Recombinant DNA: Example Using Insulin

How To Make Identical Genomes



  Recombinant DNA: How Genes Are Transferred

Basic genetic engineering (GE) takes donor DNA from one organism or type of cell and places it into the DNA of another organism or type of cell.

Move your mouse over each picture to see how recombinant DNA is made using GE.

  1. Isolate gene
  2. Prepare target DNA
  3. Insert DNA into plasmid
  4. Insert plasmid back into cell
  5. Plasmid multiplies
  6. Target cells reproduce
  7. Cells produce proteins

1. Isolate Gene

The gene for producing a protein is isolated from a cell. The gene is on the DNA in a chromosome. Special DNA cutting proteins are used to cut out certain sections of DNA. The gene can be isolated and then copied so that many genes are available to work with.

2. Prepare Target DNA

In 1973, two scientists named Boyer and Cohen developed a way to put DNA from one organism into the DNA of bacteria. This process is called recombinant DNA technology. First, a circular piece of DNA called a plasmid is removed from a bacterial cell. Special proteins are used to cut the plasmid ring to open it up.

3. Insert DNA into Plasmid

The host DNA that produces the wanted protein is inserted into the opened plasmid DNA ring. Then special cell proteins help close the plasmid ring.

4. Insert Plasmid back into cell

The circular plasmid DNA that now contains the host gene is inserted back into a bacteria cell. The plasmid is a natural part of the bacteria cell. The bacteria cell now has a gene in it that is from a different organism, even from a human. This is what is called recombinant DNA technology.

5. Plasmid multiplies

The plasmid that was inserted into the bacteria cell can multiply to make several copies of the wanted gene. Now the gene can be turned on in the cell to make proteins.

6. Target Cells Reproduce

Many recombined plasmids are inserted into many bacteria cells. While they live, the bacteria's cell processes turn on the inserted gene and the protein is produced in the cell. When the bacterial cells reproduce by dividing, the inserted gene is also reproduced in the newly created cells.

7. Cells Produce Proteins

The protein that is produced can be purified and used for a medicine, industrial, agricultural, or other uses. Check out the Uses section to see how GE is used.

Explore More: Genetic Engineering
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