More Recent Comments

Sunday, December 16, 2007

Taking the Link Out of Dr. Sharon's Blog

Yesterday Dr. Sharon (Sharon Moalem) posted a silly article about junk DNA [Please Take the Junk Out of DNA]. I've already quoted the silly parts and took note of the fact that I had made a comment on his website. That comment never appeared; instead there's now a single comment that happens to be favorable.

In his original posting Sharon Moalem said,
The idea of junk came out of the central dogma (this is not some Politburo manifesto) because some people erroneously believed that if DNA wasn’t used to make a functional protein than it must be like Grandma’s plastic covered couch, junk.
The words "central dogma" (above) liked to my article [The Central Dogma of Molecular Biology]. In that article, I give the correct version of the Central Dogma,
... once (sequential) information has passed into protein it cannot get out again.
                                                                         (F.H.C. Crick, 1958)
Anyone with a brain can see that Sharon Moalem's statement looks very, very silly once you realize what the Central Dogma really means.

What would you do if you were "Dr. Sharon"? I'll tell you what I would do. I would read the comment I left on his blog then re-read the article on the Central Dogma. I would recognize that I made a mistake and modify my article accordingly. Perhaps I would remove the sentence implying that the concept of "junk" came out of the central dogma. That's what I would do. That's what any rational person would do.

What did "Dr. Sharon" do? He removed the link to my article on the Central Dogma.

Oh dear. That looks bad, doesn't it?

UPDATE: (Sept. 2012) Now his entire post has disappeared.


  1. Yep. It looks bad.

    I knew something was up when I went to his article and tried to find your comment.

    At that time he had zero comments. I guess he has no vanity. Most bloggers would prefer to have at least one comment... as opposed to 0.

  2. I guess my question is tangential... is the central dogma at all useful? It describes narrowly a couple of properties of one type of biological information (primary sequence). There are many, many, many more ways of encoding and representing information in biological networks, all of which have their own features in terms of how information can flow, it's heritability, stability. Is there any strong pedagogical or scientifically compelling reason to have the central dogma kicking around? It's not central, and by Crick's own admission it's not dogma (he says he didn't know what the word meant at the time).

  3. Yes it is central. The fact that there is no "reverse translation" from protein sequences back to nucleic sequences is a basic and crucial fact of biology, which among other things shows why Lamarckian mechanisms of evolution are unlikely.

  4. So we have the "9 possible ways" for information to flow between 3 major classes of biological macromolecules. I would argue that most (if not all) of them happen, and the only way to keep the central dogma "true" is to restrict it (as Crick did parenthetically) to primary sequence information. This is a very important type of information, but I don't think the particulars of its "flow properties" are central to understanding information exchange in cell biology in general. Maybe it's central to countering Lamarckism (if that counts as useful today), but it's suppsed to be the central dogma of molbio, not evolution. I just think the term gives it a confusing and unnecessary weight.

  5. The basic molecular biology of primary sequence information flow, largely elucidated by the mid-1960s, might seem old and fuddy-duddy to you compared to more "glamorous" topics like DNA modification. But that attitude IMHO would be a big mistake. Primary sequence is by far the highest-bandwidth carrier of biological information; it's the framework of biology, other things are more like decorations on the framework. So the fact that this by far most important information channel operates only in the nucleic acid --> protein direction and is not reversible remains one of the most profoundly important facts about biology, which would look very different in a world where this was not the case.