Dispatches from the cutting edge... part 2 and a half

In my earlier posts on the research by Keiichi Namba, Tohru Minamino and their colleagues on the bacterial flagellum:

• Dispatches from the cutting edge of flagellar biology, part 1
  
• Dispatches from the cutting edge of flagellar biology, part 2

I promised to upload the latest movie from the team. Keiichi gave me permission to upload it on to YouTube, but at 30 minutes it is too long to go there, so I have placed it on Google Video. Ignore the rather cheesy opening and revel in the fantastic animations:

And note, although Namba et al talk of the flagellum as a machine, they just laugh at the notion of intelligent design!

While on the subject of flagellar biology and evolution, Nick Matzke recently drew my attention to these two papers:

• A channel connecting the mother cell and forespore during bacterial endospore formation PNAS September 30, 2008 vol. 105 no. 39 15100-15105
  
• A novel pathway of intercellular signalling in Bacillus subtilis involves a protein with similarity to a component of type III secretion channels. Mol Microbiol. 2008 Jul;69(2):402-17.

which both claim to have identified homology between a flagellar protein FliF, that forms the M-ring in the bacterial inner membrane and SpoIIIAH a protein involved in spore formation from the Gram-positive bacterium Bacillus subtilis. If true, this would be another step forward in undermining the argument made by intelligent design advocate Scott Minnich that lack of homology for flagellar proteins provides support for the ID position. 

However, as both sets of authors used a similar rather risky method for assigning homology, which covers only part of the protein, I am not entirely convinced by their claims. Full proof will come only from comparisons of the structures of the proteins. In the mean time, we should keep an open mind and it would be worrying if tentative claims of homology turn into dogmatic statements of fact before conclusive evidence is in. But the claims of homology do at least provide a framework for future research. Watch these proteins!