Scene 1

[Scene 1 begins by zooming in on a vertically oriented DNA helix set on an empty blue background. The helix is comprised of two ribbon-like vertical spiraling grey structures, each of which has a series of colored rungs running its entire length. The rungs, or bases, which extend horizontally from each spiral, are red, yellow, green and purple. The bases on one spiral are bound to those on the other, creating horizontal base pairs that connect the two spirals. The base pairs are matched by color: red/green and yellow/purple. The bases are also shaped differently, so that a red base fits exclusively into a green base and a purple base fits exclusively into a yellow base.

The animation closes in on the helix and stops.]

DNA and Genes

DNA consists of four different nucleotides -- adenine (shown as a red base), cytosine (yellow base), guanine (purple base), thymine (green base). Each of our genes is made up of a specific sequence of these four nucleotides.

Scene 2

[Two strands of DNA are shown. Three yellow bases have Methyl groups - shown as circles surrounded by three Hs.

As the base pairs separate, duplicate strands of DNA, shown as grey ribbon-like structures, enter the scene, creating two duplicate DNA helixes, each with three Methyl groups.]

Normal DNA Methylation

Some cytosines within each gene can be "tagged" with a methyl group, which indicates that gene is turned off. After DNA replication, special proteins add methyl groups to the newly formed strands to make sure the "tagging" is consistent from one generation to the next.

Scene 3

[A DNA helix is shown in the nucleus of a normal cell - shown as a pink oval. The scene recedes, pulling out to show the unblemished back of a male patient.]

Normal Cells

By ensuring that the proper genes are turned on or off, each cell can perform its specific role in our body and stay healthy.

Scene 4

[Two strands of DNA are shown. Three yellow bases have Methyl groups - shown as circles surrounded by three Hs.

In this scene, the resulting DNA strand at the top of the screen only has two methyl groups - illustrating hypomethylation - and the strand at the bottom of the screen has five methyl groups - illustrating hypermethylation.]

DNA Methylation Errors

Rarely, mistakes can occur after DNA replication, resulting in too many (hyper-) or too few (hypo-) methyl groups. Environmental agents, such as radiation, cigarette smoke, or other chemicals, can also produce DNA methylation errors.

Scene 5

[A mutated DNA helix is shown in the nucleus of a cancer cell - shown as an irregularly shaped blue cell. The scene recedes, pulling out to show a blue mass on the back of a male patient.]

Errors in Methylation Can Lead to Cancer

Over time, methylation errors can build up in some cells. If the wrong proteins are turned on or off, cells may begin rapidly growing, eventually becoming cancerous and forming a tumor.