Saturday, March 6, 2010

Mutation - Part One

Although I have no source of reference to validate this statement, I'd say that 80% of mutations in the movies are caused by viruses. Let us examine one of these movies in great detail, as it provides interesting insight into the follies of science.

The brilliant thing about I Am Legend is that the movie tells the story of a genetic mutation that will ravage the human and dog population, any day now. The fall of man is a measles virus genetically re-engineered by scientists looking for a cure for cancer.

People have known for more than 100 years that certain viruses have the potential to treat cancer and shrink tumors(1). As a matter of fact, the early part of the 20th century saw attempts to treat cancer with measles, rabies and smallpox. Using herpes virus to battle cancer is also of interest to researchers.

Herpes. Cure your cancer, make sex awkward(2).

A virus is essentially a packet of genetic information for making more viruses. First the virus infects a target cell. Through a series of steps instigated by viral enzymes, the virus will insert its own strand of DNA (genetic information) into the DNA of the host cell. Viral DNA is now a part of the cell's genetic make-up and the host cell will get busy making new viruses. Any time the cell reproduces, it also reproduces the viral DNA in its nucleus as if it were its own.

For you trivia buffs, here's a representation of viral reproduction.

To over-simplify the process, using the tiny graphic, above:
1. The virus binds to the cell wall
2. The virus fuses with and enters the cell
3, 4, 5. The virus inserts its genetic material into the DNA in the nucleus of the host cell.
6, 7. The cell starts making viral components.
8. The cell assembles the virus
9. The new viruses start budding out of the cell membrane, going off to infect other cells.

Easy peasy!

The general idea is that you engineer an oncolytic adenovirus to target only cancer cells. The virus infects the cell, uses the tumor cell to make more virus, and kills the infected cell as the new viruses burst out of it. The newly made viruses can then infect other local tumor cells, or travel through the bloodstream to infect metastasized(3) tumor cells in other parts of the body, and destroy them too.

Additionally, the use of these viruses in this process may hyper-stimulate a body's immune response. Heightened targeted immune response might lead to the body being able to fight its own cancer.

What could go wrong?

Mutation ... that's what!

Don't let this happen to you!
At least she doesn't have herpes.

During viral reproduction a lot of genetic coding is interrupted, replicated, inserted and re-replicated. All of these steps for making copies of viral DNA mean that there is a lot of opportunity for MUTATION. Not just people cellular mutation, but viral mutation, too.

Look out! I Am Legend takes place in Manhattan in 2012!

Coming up next - more about viruses and what to expect in two years!

1. Here is a link to a pdf of the article Virotherapy As An Approach Against Cancer Stem Cells, by Camilla Ribacka and Akseli Hemminki. Highly entertaining. As I read it, I found myself wishing that I Am Legend's Dr. Krippin (Emma Thompson), the virologist to blame for the entire horror-to-come, had been given a couple of lines reflecting a glimmer of what was written here. It wouldn't have to be too complicated, just something to make her sound more knowledgeable.
2. There are actually a few different types of herpesvirus out there, like the one that causes chicken pox. But the joke is better if it appears that you have to acquire a sexually transmitted disease in order to cure your cancer. Ha ha!
3. Cancer cells that have spread to other parts of the body.


  1. I am sure your comment was witty and insightful. I just wish I could read it.

  2. Shit! Good thing I'm preparing for this!!