Article published in French in Uniscope n° 515 (magazine of the University of Lausanne), January 15 - February 28 2006, pages 22-23. PDF
The prophets of the Bible were probably unaware of the existence of bacteria. That was a mistake: these unicellular organisms turn out to be dread sneaks. In this surprising adventure, life sciences meet linguistics and theology.
DNA can be compared to a text and its four basic units to an alphabet. This analogy led biologist Claude-Alain Roten to wonder whether it was possible to use genomic analysis, based on the examination of characters, in order to decipher literary works. His unconventional approach deserves to be explained in more detail.
DNA’s four units are represented by the letters A, T, G and C and form a coded sequence. Claude-Alain Roten analyzes the distribution of these letters by capturing the complete genetic code of bacteria. For examples, he isolates distinct parts of the DNA, characterized by a higher or lower frequency of one or more letters. The arrangement of these units reveals certain changes or mutations which the bacteria have undergone during their evolution.
A text such as the Old Testament also results from a long evolution. Can Roten’s investigation method reveal something about it? Will the simple frequency of the letters highlight at which period the many books were written, reveal potential later additions or even the "signature" of the authors. In other terms, is it possible to rebuild the Bible’s evolutionary History like biologist do with a living organism? Based on the single principle of occurrences, the process requires basically no knowledge of Hebrew. "We use the brute force of the computer. When people ask me if I read Hebrew, I have to confess I don’t," says the biologist.
FROM ENCRYPTED VIRUSES TO BIBLE WRITERS
An example is given by PhD student Alexandre Panchaud work. He used the DNA walk method (see box) as part of his student assignment and highlighted irregularities on a bacteria’s DNA curve (see figure below). It turned out later that these abnormalities belonged to encrypted viruses, which had inserted their own genome into that of the bacterium. "It is as if we had included a smaller text in Italian in the middle of a French text. One could highlighting the interference of Italian without knowing any of these two languages,"says Roten.
DNA curve of a bacterium based on the letters T and A. Black: "regular" genes Red: "irregular" genes, characterized by a high frequency of A. This actually is the DNA of a virus parasitizing the bacteria.
Adapted to the twenty-two Hebrew letters of the Old Testament, the same method already gives promising results. "We have spotted similar phenomena even within the books of the Bible. Some passages visibly differ from most of the text. The curves analysis betrays their presence exactly as it betrayed the presence of the viruses within the bacterial genome" (see figure below). Does this show a contribution from a secondary author, or a subsequent addition showing an evolution of Hebrew? It could even be an insignificant variation of style. At this moment of the investigation, only someone capable of conducting a standard analysis can answer these questions. Expert of the Old Testament and theologist Thomas Romer got down to the task.
Curve of the entire Old Testament, based on the Hebrew letters vav and yud. Black: "regular" excerpts RED: "irregular" excerpts, characterized by a low frequency of yud. It could be the mark of schools or particular authors. The results of this analysis are under review.
OTHER TEXTS TO BE ANALYZED
Positive results have already been obtained after the analysis of the whole Old Testament. Chapters generally show similar curves when conventional critic attributes them to a same author or estimate their writing to have taken place at the same period. These data are undoubtedly useful in setting up a chronology of the text, especially as the process can be further refined. "With our scientific method, we can easily highlight the authorship or eras of the different texts," says Roten. "And we do it without even understanding the meaning". Other works are currently under such analysis, like the Iliad and the Odyssey, whose Homeric authorship raises doubts among experts. While this method cannot fully substitute a historical or linguistic investigation, it could well constitute a new valuable tool for text analysis.
Claude-Alain Roten already figures other possible applications for his method, most particularly in the field of forensics. Many methods already enable to discover the author of an anonymous text - examination of the DNA traces left on the document, graphology or even style analysis. We could add up a new one: the analysis of the occurrence of letters. "A few years ago in the United States, a scientist in need of recognition sent his rivals parcel bombs, usually accompanied by an anonymous letter," says Claude-Alain Roten. Letters occurrence could have determined whether the messages were from a single author. It could have helped identifying him by comparing the anonymous letters with his scientific publications or private correspondence.
WHAT IS DNAWALK?
Unwinding the DNA thread of a bacterium, such as Streptococcus pyogenes, reveals a text long of about one million eight hundred thousand letter, which entirely determine the species identity. It is easy to represent such a genome: the four letters correspond to the cardinal points of a two-axis graph. The DNA chain gradually forms a curve as it unfolds. For example, variations make it possible to take into account only a pair of two letters and other graphic approaches of the genome. Developed in the 90s and commonly referred to as the DNA Walk, this method can sometimes lead to surprising conclusions (see illustration above).
In the United States, Christian fundamentalists are getting ever greater control of education. In accordance with their literal reading of the Bible, many of them oppose the evolution theories and support creationism: all life forms would have appeared spontaneously. The administration, which wants to please these many voters, gives creationism more and more importance. In some states, schools are now required to teach this theory. Universities are stormed by religious groups trying to spread the Good Word. Needless to say, an overwhelming majority of researchers see absolutely no scientific value in creationism.
Last April, the prestigious journal Nature rang the alarm bell. It featured an oracular cover warning, not without irony: "This journal contains material on evolution. Evolution by natural selection is a theory, not a fact. This material should be approached with an open mind, studied carefully and critically considered." In the same vein, the American Museum of Natural History of New York City recently set up a major exhibition on evolution.
"In a way, I have reversed the approach of creationists," says Claude-Alain Roten: "They use the Bible to explain biology, and I use a biological method to measure the Bible’s historicity". His method shows that, in a similar way to living organisms, the Bible results from a long evolution, and that it cannot be read literally. "I'm not commenting on the religious dimension of the text. My provocation aimed at creationist circles, I would be happy to sow the seed of doubt among them."