You hear a lot about DNA and deciphering the genome. In the November 6, 2010 issue there is a great article about this. This is a very short excerpt:
No one really knows all the genetic parts needed to make a human being. Exactly how many genes make up the human genome remains a mystery, even though scientists announced the completion of the Human Genome Project a decade ago. That effort was supposed to reveal all of the protein-producing genes needed to build a human body. "Not only do we not know what all the genes are, we don't even know how many there are." –Steven Salzberg of the University of Maryland in College Park.
If you're interested in genetic testing, gene therapy, and so forth, you should look up the whole article.
Here's my favorite part. One would assume that the more complicated (advanced?) an organism is, the more complicated its genome would be. Man, the paragon of animals, ought to be way ahead of say, a chicken. And so we are. But look who tops us:
The next time you're thinking God sits up nights to admire us (I stole that from Mark Twain), fix yourself a glass of grape juice. Then consider that perhaps man is more than just an animal body, that there's more to us than meets the eye (or the microscope).