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Wednesday, February 07, 2007

The Wrong Version of the Genetic Code

Hsien Hsien Lei over at Genetics & Health has posted a recommendation for winter reading [Freakenetics: The Freakonomics of Genetics]. She suggests that Survival of the Sickest by Dr. Sharon Maolem and Jonathan Prince might be a good read.

Here's a quotation from the book,
…DNA isn’t destiny–it’s history. Your genetic code doesn’t determine your life. Sure, it shapes it–but exactly how it shapes it will be dramatically different depending on your parents, your environment, and your choices. Your genes are the evolutionary legacy of every organism that came before you, beginning with your parents and winding all the way back to the very beginning. Somewhere in your genetic code is the tale of every plague, every predator, every parasite, and every planetary upheaval your ancestors managed to survive. And every mutation, every change, that helped them better adapt to their circumstances is written there.
Now, this may or may not be a good book but I'd like to use the quotation as a way of introducing one of my pet peeves. In doing so I don't mean to impugn the sense of what's said in the quotation.

The sequence of DNA in your genome is not the "genetic code." The Genetic Code is the lookup table shown in the accompanying posting [The Real Genetic Code]. The sequence of nucleotides in your genome is the message that may be interpreted using the genetic code in the same sense that the message received over a telegraph may be interpreted using the Morse Code.

It's appropriate to say that somewhere in this message is the record of your survival but it's inappropriate to say the genetic code is altered by evolution. (At least in this context.)

I realize that when science writers use the term "genetic code" they are writing for the general public. Those writers may know the difference between the real Genetic Code and what they say in a popular article. They may know the difference, but somehow I doubt it. Most people who know the difference wouldn't make the common mistake of confusing the code with the message.

In any case, the book would be no less accurate if it talked about the message in your genome instead of the genetic code. So why not use the correct term?

Similarly, I'm getting tired of hearing about the latest sequencing project that "cracked" the genetic code. The real Genetic Code was cracked forty years ago in an astounding display of technology that earned the decoders a Nobel Prize. What sequencing projects do is determine the sequence of a genome, not its genetic code. The standard Genetic Code is (almost) universal. All species use the same Genetic Code.


  1. Thanks for pointing that out

  2. Yes, I appreciate it as well. As a grad student in English, I nonetheless have a strong interest in biology and genetics, and it's helpful to me to have that information cleared up.

  3. hsien hsien lei is a she. genetically an XX that is. no SRY.

  4. I sympathize. But I don't think programmers are strict either. They mix code and program and say program code and coding programs, while it is really only the code/decode process that should be called so.

    One reason for that is that everything is coded in levels, so what is a code instruction at one level is interpreted as a program for the next, until your program finally get interpreted as microcode in the hardware.

    But the real reason here is probably that "the genetic code" has more oomph than "the sequence of the genome". :-)

  5. According to the press, all these genome projects are decoding genomes or mapping genomes.