the evolving mind

Now this is a very exciting development:

One of the most enduring questions is how life could have begun on Earth. Molecules that can make copies of themselves are thought to be crucial to understanding this process as they provide the basis for heritability, a critical characteristic of living systems. New findings could inform biochemical questions about how life began.

Now, a pair of Scripps Research Institute scientists has taken a significant step toward answering that question. The scientists have synthesized for the first time RNA enzymes that can replicate themselves without the help of any proteins or other cellular components, and the process proceeds indefinitely [from How Did Life Begin? RNA That Replicates Itself Indefinitely Developed For First Time.]

(Insert the sound of Al Pacino saying “hoo-ah!” here.)

This sentence in the news release stood out to me.

In the modern world, DNA carries the genetic sequence for advanced organisms, while RNA is dependent on DNA for performing its roles such as building proteins.

Is DNA a code or a sequence? In a previous post I argued against the use of the term “code” (and “language” and “instructions”) when talking genetics and evolution. And it prompted a very thought-provoking comment, including this thought :

Claiming that the “genetic code” is actually not a “code” prompts the question of why it has that name. Without the proper definition of “code”, the question can’t be answered accurately.

To which I say, “hoo-ah!” Good point.

Before drifting off to bed last night I did some thinking about why I don’t consider DNA a code. Or, put another way, why “code” isn’t the best word to describe genetic material. And this is what I came up with –

Once you decipher what the basic units of a true code signify (be it a spoken language, hieroglyphics, or a Morse-like code) you can then understand the meaning of any new, unique string of those units. With DNA that doesn’t seem to be the case. The “meaning” of any fully unique string of genetic material can’t be determined from the basic units. There is no Rosetta-Stone-like key to DNA that enables us to immediately grasp what any all segments “say.”

Of course, I could be wrong. In which case, I hope to hear about it.

Technorati Links: origins, semantics

Trackback URI | Comments RSS