Bacteria Genomes Are Degrading

 
At one point in his talk last night Kirk Durston mentioned the bacterial flagella. He acknowledged that the "Darwinists" have proposed an evolutionary pathway from a Type III secretory structure to flagella.

This pathway is improbable, according to Durston, because flagella are more complicated than secretory pores so flagella have to evolve first.

What? Yes, that's right. Scientists have now shown that the most primitive bacteria were very complex and evolution has been all downhill from then on. Modern bacteria are less complex. Thus the type III secretory apparatus had to evolve from the more complex bacterial flagella. (The actual situation is complicated [Evolution in (Brownian) space: a model for the origin of the bacterial flagellum]. What I'm addressing here is the claim of general loss of information in bacterial evolution.)

I suggested that this was bull not correct and Durston responded with a slide showing the scientific papers that proved it. The most important paper was

Mira, A., Ochman, H. and Moran N.A. (2000) Deletional bias and the evolution of bacterial genomes. Trends Genet. 17:589-96. [PubMed]

I asked Durston what would happen if I called Nancy Moran (no relation, that's her above) and asked her whether she agreed that primitive bacteria were complex and all modern bacterial lineages are losing information. He affirmed that she would and that's what modern evolutionary biologists are saying. There are other papers that say the same thing. He accused me of not being aware of them.

This is the abstract of the Mira et al. (2000) paper.

Although bacteria increase their DNA content through horizontal transfer and gene duplication, their genomes remain small and, in particular, lack nonfunctional sequences. This pattern is most readily explained by a pervasive bias towards higher numbers of deletions than insertions. When selection is not strong enough to maintain them, genes are lost in large deletions or inactivated and subsequently eroded. Gene inactivation and loss are particularly apparent in obligate parasites and symbionts, in which dramatic reductions in genome size can result not from selection to lose DNA, but from decreased selection to maintain gene functionality. Here we discuss the evidence showing that deletional bias is a major force that shapes bacterial genomes.

I think it's pretty obvious from the abstract that they're discussing a particular problem in bacterial evolution; namely selection for small compact genomes. This point is clear in the paper as well.

At no point in the paper do the authors suggest anything close to what Durston says. There's no mention of primitive bacteria having the full complexity of all modern species including the myxobacteria and photosynthetic bacteria etc. Why in the world do the Intelligent Design Creationists have to lie about things like this? (I assume it's a lie because the only other possibility is ignorance and a Ph.D. student in biophysics can't be stupid enough to misunderstand such a key principle of evolution, right?)

Naturally in a forum like this Durston had me at a disadvantage. He was displaying the scientific papers and I had to admit that I had not read them recently enough to comment. The point was not lost on some members of the audience. The atheist scientist was trumped by the religious graduate student who was more aware of the scientific literature.

"Frustrating," doesn't begin to cover it ...

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