Geneticists are acquiring a taste for punctuation. Yesterday, for example, a study on "junk" DNA -- that is, stretches of it without known purposes -- in the journal Science was published to the accompaniment of a press release with comments from two of the authors. "Some of the 'junk' DNA might be considered 'punctuation marks,''' said Victoria Lunyak of the University of California at San Diego, "commas and periods that help make sense of the coding portion of the genome." Likewise, her colleague Michael Rosenfeld said, "Without boundary elements, the coding portion of the genome is like a long, run-on sequence of words without punctuation."

The study itself, "Developmentally Regulated Activation of a SINE B2 Repeat as a Domain Boundary in Organogenesis," speaks more cautiously of "establishment of functionally distinct chromatin domains" and "putative boundary elements." The idea is that DNA could not do its work-- building proteins, that is -- if it didn't get organized into functional domains that are like the groupings provided by syntax and expressed by punctuation marks.

DNA has long been called a code, which is not only replicated, but also read, transcribed and translated, and genes are "expressed." Almost rapturously, some speak of the genome as "the book of life," which is a Biblical phrase. More modestly, others call DNA an alphabet for a language of which the grammar and syntax are yet to be discovered (for example, Richard A. Young of the Whitehead Institute, an affiliate of MIT).

As recently as 2000, a New York Times story, under the headline "Reading the Book of Life," lamented that "evolution has neglected to provide even the punctuation to show where genes stop and start .... The lack of punctuation makes the genes hard to identify."

But now the commas and semi-colons of life seem to be surfacing. In 2006, the Proceedings of the National Academy of Sciences had an article called "Transcription regulatory elements are punctuation marks for DNA," saying that punctuation is an inhibiting factor during "head-on collisions" and an attenuating one during "co-directional collisions" --a good thing, I gather.

A professor of pharmacology at Mc-Gill, Moshe Szyf, working in an emerging field called epigenetics, has spoken of markings on the genome that work like punctuation; cells can become cancerous because of a "loss of proper punctuation" that changes "the expression and the meaning."

It is remarkable how scientists are so attracted to images that attribute consciousness to physical processes, at a time when quite a few of them are trying to reduce consciousness to just such a process. Of course, geneticists also liken the workings of DNA to the mechanical process of printing, which is itself a tool to transmit conscious language. So the imagery of machines and souls can peacefully coexist.

When I try to read such studies, I understand very little, but I know a thing or two about punctuation. The scientific metaphor-makers think of punctuation as serving syntax, but there is a great distinction between syntactic, or "logical" punctuation, on the one hand, and elocutionary, or "rhetorical" punctuation, on the other hand.

For much of history, the latter prevailed. The marks were almost a musical notation, for reading aloud (or in one's head), telling a reader when to pause and for how long, with signs for varying intervals ranging from the comma for a short stop, through the semi-colon and colon to the full stop.

In English, the shift to logical punctuation is often dated to around 1617, when the playwright Ben Jonson wrote a book on grammar in which he advocated it. Yet in his conclusion he eloquently articulates the importance in speech of breath and pauses for breath.

Though the reigning doctrine favours the logical variety, and tries to strictly separate pause from punctuation, H.W. and F.G. Fowler make clear in their classic The King's English that it is not practical or desirable to do so. The series of marks for shorter to longer pauses still do both logical and rhetorical work.

I am a secret sympathizer with rhetorical punctuation. Maybe a time will come when DNA, too, will sing and persuade.