Watch the animation on the left side of the screen to see how bacteria share genes that encode resistance to antibiotics. This demonstration has been adapted from an animation developed by HHMI international research scholar B. Brett Finlay, Ph.D., for the 1999 Holiday Lectures on Science, 2000 and Beyond: Confronting the Microbe Menace.

To view the animation, manipulate the controls at the bottom of the view screen. Expect several pauses as the text in this panel updates to describe the relevant step in the animation.

Part 1: The bacterial genome

The animation begins with two bacteria meeting. Each one contains its own chromosome. Above the chromosome of one bacterium (bacterium A) is a plasmid, a portion of the bacterial genome that is separate from the chromosome. The plasmid of bacterium A is also known as Resistance (R) factor. It contains genes that encode different traits and can, as you will see, be transferred from one bacterium to another, and even between different species! In the case of this animation, the R factor encodes a molecule that provides resistance to the antibacterial drug X.