That is, if you’re not stupid. If you’ve had to deal with creationist dumbitude, you’ve probably encountered what they call ‘irreducible complexity.’ By that, they mean that some structures are so complex, only
a Vorlon an Intelligent Designer could have made them. Of course, what this really means is that they’re too fucking lazy and stupid to strap on the ol’ thinkin’ cap and figure it out.
Anyway, one of the cool bits of biology creationists like to muddy up are the bacterial structures responsible for motility–the cool molecular gizmos that allow bacteria to move around (people often call this swimming, but it’s actually more like drilling; when you’re the size of a bacterium, water is like molasses). They often look like little motors (at least in stylized drawings), so, of course, they must be designed.
Well, a recent paper looked at the gliding motility system in Myxococcus xanthus, a bacterium that not only hunts in a large amoeba-like pack, but also then forms fruiting bodies, which look like this:
(this is actually from Chrondromyces crocatus, but it was the nicest picture I could find. So sue me.here)
Only the bacteria in the ‘fruit’-like part reproduce, the rest make up the stalk and then die. So gliding motility is kinda important. So did the Intelligent Designer, erm, design fruiting bodies. Nope (boldface mine):
Bacteria glide across solid surfaces by mechanisms that have remained largely mysterious despite decades of research. In the deltaproteobacterium Myxococcus xanthus, this locomotion allows the formation stress-resistant fruiting bodies where sporulation takes place. However, despite the large number of genes identified as important for gliding, no specific machinery has been identified so far, hampering in-depth investigations. Based on the premise that components of the gliding machinery must have co-evolved and encode both envelope-spanning proteins and a molecular motor, we re-annotated known gliding motility genes and examined their taxonomic distribution, genomic localization, and phylogeny. We successfully delineated three functionally related genetic clusters, which we proved experimentally carry genes encoding the basal gliding machinery in M. xanthus, using genetic and localization techniques. For the first time, this study identifies structural gliding motility genes in the Myxobacteria and opens new perspectives to study the motility mechanism. Furthermore, phylogenomics provide insight into how this machinery emerged from an ancestral conserved core of genes of unknown function that evolved to gliding by the recruitment of functional modules in Myxococcales. Surprisingly, this motility machinery appears to be highly related to a sporulation system, underscoring unsuspected common mechanisms in these apparently distinct morphogenic phenomena.
In short, the genes involved in cellular movement seem to closely related to the same genes involved in making the fruiting bodies (note: it’s not the same genes).
I realize creationists will simply argue that the two systems aren’t similar enough, and therefore they can’t be related, but they, sadly, are stuck on stupid. For the rest of us, though, it’s a pretty cool paper.
Cited article: Luciano J, Agrebi R, Le Gall AV, Wartel M, Fiegna F, et al. 2011 Emergence and Modular Evolution of a Novel Motility Machinery in Bacteria. PLoS Genet 7(9): e1002268. doi:10.1371/journal.pgen.1002268