DNA Is Like a Videotape:

An Analogy in Contrast to

"DNA is like a Blueprint"

DNA is often called the "genetic blueprint" of an organism. But DNA is more like videotape than a blueprint.

Videotape is a tape--it's linear.

• It carries information.
• The information is encoded.
• The information has to be translated.
• We use a VCR and a TV to translate the information.
• The information produces sounds and pictures: scenes.
• We can make copies of a videotape.
• We can edit videotape: for example, we can take a scene from one movie and splice it electronically into a copy of a second movie.
• We can make copies of the edited tapes.
• Tapes of two different movies are composed of the same tape, but the information recorded in them is different.
• Tapes can come in different formats: for example, VHS and Beta.

DNA is a tape--it's linear.

• It carries information--genetic information.
• The information is encoded.
• The information has to be translated.
• Cells translate the information on DNA.
• The information on DNA makes traits: genes
• Cells can copy DNA.
• DNA can be edited: for example, we can take DNA containing one gene from an animal (for example, the gene for insulin from humans) and splice it biologically into the DNA of a bacterium.
• That bacterium can multiply, and its offspring will contain the insulin gene.
• Those bacteria can make the human insulin protein.
• DNA from different organisms is chemically much the same format, (unlike videotape); so a gene from a bacterium can be inserted into and expressed in a plant or an animal.

As with all analogies, this one eventually breaks down. Only DNA copies itself and only cells grow; videotapes don't copy themselves and are not living organisms. But the analogy is useful because of all the other similarities between DNA and videotape.