GE In-Depth GE In-Depth
     

GE Basics
Locating Genetic Information

Timeline of GE

Processes
Recombinant DNA:
How Genes Are Transferred
   

Recombinant DNA: Example Using Insulin

Cloning:
How To Make Identical Genomes

 

 

  Recombinant DNA: Example Using Insulin
 

Genetic engineering processes can make human insulin. Human insulin DNA is placed into the DNA of a second organism. The host organism becomes an insulin-producing factory.

People with diabetes (called diabetics) do not correctly produce or use their insulin protein. The insulin protein helps control how much sugar is in your bloodstream. Millions of diabetics need to take insulin. Insulin from cows and pigs has been used since the early 1900s to treat diabetes. Now human insulin protein can be mass-produced through genetic engineering processes.

Move your mouse over each picture to see how to produce insulin through GE.

  1. Isolate Gene
  2. Prepare Target DNA
  3. Insert DNA into Plasmid
  4. Insert Plasmid back into cell
  5. Plasmid multiply
  6. Target Cells Reproduce
  7. Cells Produce Proteins

1. Isolate Gene

The gene for producing HUMAN insulin protein is isolated. The gene is part of the DNA in a human chromosome. The gene can be isolated and then copied so that many insulin genes are available to work with.

2. Prepare Target DNA

In 1973, two scientists named Boyer and Cohen developed a way to take DNA from one organism and put it in the DNA of bacterium. 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 open.

3. Insert DNA into Plasmid

With the plasmid ring open, the gene for insulin is inserted into the plasmid ring and the ring is closed. The human insulin gene is now recombined with the bacterial DNA plasmid.

4. Insert Plasmid back into cell

The bacterial DNA now contains the human insulin gene and is inserted into a bacteria. Scientists use very small needle syringes to move the recombined plasmid through the bacterial cell membrane.

5. Plasmid multiply

Many plasmids with the insulin gene are inserted into many bacterial cells. The cells need nutrients in order to grow, divide, and live. While they live, the bacterial cell processes turn on the gene for human insulin and the insulin is produced in the cell. When the bacterial cells reproduce by dividing, the human insulin gene is also reproduced in the newly created cells.

6. Target Cells Reproduce

Human insulin protein molecules produced by bacteria are gathered and purified. The process of purifying and producing cow and pig insulin has been greatly reduced or eliminated.

7. Cells Produce Proteins

Millions of people with diabetes now take human insulin produced by bacteria or yeast (biosynthetic insulin) that is genetically compatible with their bodies, just like the perfect insulin produced naturally in your body.

Explore More: Genetic Engineering
Copyright 2004, Iowa Public Television
The Explore More project is supported by funds from the
Roy J. Carver Charitable Trust
and the USDE Star Schools Program.