Big Mysteries, Tiny Organisms

Do you think about microbes very much? -- probably not. Most people pay attention to life's smallest creatures only when something goes wrong, but microbes are amazing organisms, full of scientific mysteries with deep implications for the question of the origins of life. Let me tell you about one such mystery. Biologists have recently developed technologies that allow them to sequence, or read, large amounts of DNA. DNA carries the information to build proteins, the nano-level machines that do the work inside cells. Biologists can now "read" the entire genomes of microbes -- their complete volume of DNA -- and compare that information to other known genomes. Think of this as comparing the words in a library of books. Just as we have dictionaries that contain the words in the English language, so biologists have computer databases that record the DNA sequence they've discovered. Anyone who wants to publish a newly discovered gene sequence records it in these databases. One such database is called GenBank. If you've found a new gene, you can take that information to GenBank and look for matching sequences. Like a student who looks up unfamiliar words in the dictionary, biologists compare newly discovered genes to those already recorded in GenBank. The comparison then tells them what their gene does. It may match the ones that make a protein for metabolism, or transport, or some other cellular job. Now, here's the mystery. Many of the genes that biologists have discovered have no matches in GenBank. These are unique genes, and no one knows what they do. As biologists have compiled the "words" in the genetic library of microbes, many of them belong only to the species where they were found. These sequences have been dubbed "orphans." Russell Doolittle of the University of California notes that "In every genome examined so far, at least a quarter of the genes remain 'hypothetical,' in that no function can be ascribed." We don't know what these genes do in the cell. Biologists are fairly certain that these orphan sequences truly are genes, because they share the features that identify known genes. The sequences, says Doolittle, "look conventional in every way," but, he adds, "where these unique sequences are coming from and what they do remain baffling mysteries." You see, the main evolutionary theory for the origin of genes says that new genes arise from already- existing genes. But the orphan genes don't have detectable evolutionary parents. If they did, they wouldn't be orphans. Where did these genes come from? No one knows. What do they do? No one knows. Evolutionary theory is stumped. Scientific mysteries like this belong in the public classroom, because science thrives on unsolved problems. The best way to interest a kid in science is to pose just such a puzzle. And the best way to keep evolutionary theory honest is to challenge it with the puzzles it faces. When we do so in this instance, we see the case for intelligent design, a Creator Who gave us these purposeful genes. The evolutionists don't like it, but it's real science and real education. For further reading and information: Visit the Discovery Institute's website for information on intelligent design. Learn about GenBank at its website. Charles Colson and Nancy Pearcey, Developing a Christian Worldview of Science and Evolution (Tyndale House, 1999). Russell F. Doolittle, "Microbial genomes multiply," Nature 416 (18 April 2002): 697-700. Daniel Fischer and David Eisenberg, "Finding families for genomic ORFans," Bioinformatics 15 (September 1999): 769-762. (requires Adobe Acrobat reader) Scott N. Peterson and Claire M. Fraser, "The complexity of simplicity," Genome Biology 2 (2001): 1-8. Peterson and Fraser write, of their work on the genome of the simplest known bacterial cell, Mycoplasma: "The fact that an estimated one third of the essential set of genes in this minimal genome are of undefined function is an important result that has at least two potential interpretations. First, it draws dramatically into question a basic assumption held by many biologists that the fundamental mechanisms and functions underlying cellular life have for the most part been identified and well characterized. If approximately 100 genes in the simplest functioning cell are of unknown function and are essential to basic cellular processes, this assumption becomes quite dubious." (p. 6)

05/8/02