Buggs: TSS and the Flagellum

[Krauze]

@Rumraket

I don’t agree. While I am generally sympathetic to any endeavor that seeks to correct erroneous public statements made by scientists(and statements by Richard Dawkins are no exception), it is pretty clear Buggs’ aims go far beyond merely getting the view on the relative history of injectisome and flagellum-evolution right. As is typical of ID proponents he is appears to be trying to paint a picture where there is no workable case for flagellum evolution at all, and this is just the latest step in that endeavor.

I don’t know if that is clear at all. As @Zachary_Ardern points out, we’re using a 14 year old article as a lens to interpret all of Buggs’ current actions through.

But even if Buggs had some nefarious ultimate aim in writing his blog post, how would that affect whether his criticism of Dawkins is correct?

You’re sympathetic to attempts to correct erroneous public statements made by scientists, and you agree that Dawkins’ statements are erroneous or at least highly misleading for an audience unaware of the technical niceties of TTSS terminology. So his statements deserve correction, but someone other than Buggs should have done so?

@Rumraket

And it’s just not true that without a phylogeny implying that flagella derive from injectisomes leaves one with “nothing behind”. Dawkins could simply have said what Kenneth Miller said, that the existence of the T3SS both in the flagellum and in related structures provides an excellent rebuttal to the claim that the flagellum being irreducibly complex with respect to the motility function prevents the possibility of it’s gradual evolution.

He could, but that would have been an entirely different, and much weaker argument. Consider the point made in this thread that swim bladders evolved from lungs, not the other way around; saying “lungs could have evolved from swim bladders” is a very different thing than saying “lungs did evolve from swim bladders”.

However, I can see how Dawkins could have been misled by Miller’s article, given that Miller also brings up the injectisome as a “precursor” to the bacterial flagellum.

@Rumraket

Now this is just ridiculous I have to say. You first wrote:

I don’t want this discussion to devolve into hermeneutics. But here’s an attempt to make things clear: We were talking about a pre-flagellar TTSS. You refer me to Matzke’s TalkDesign FAQ. I go to the section of the FAQ in which Matzke adresses the plausibility of a pre-flagellar TTSS (section 3.2.3), explaining why I don’t think his arguments rise above “might’ve happened”. Whether Matzke himself used “plausible” in a stronger sense than “might’ve happened” is an open question, but I took you to be using section 3.2.3 to argue this stronger point.

No story is being changed; my comments on Matzke’s FAQ have always been directed at how I took you to be using the FAQ.

In your latest reply to me, you write:

@Rumraket

But no, I do think there are grounds for positing a TTSS ancestral to flagella, and part of those reasons are argued by Matzke in the section 3.2.3. An ancestral type III secretion system is plausible , and in 3.2.5. The relationship between type III export and the F1F0-ATP synthetase .

But if you think that section 3.2.3 provides the grounds for positing a TTSS ancestral to flagella, why do you object to me evaluating section 3.2.3 in terms of whether it provides grounds for positing a TTSS ancestral to flagella? I feel that we’re talking past each other here.

As for section 3.2.5, the F-type ATP synthase isn’t a TTSS, and rephrasing Dawkins’ argument in terms of the ATP synthase makes for a different and much weaker argument.

@Rumraket

I think there are more, for example that protein complex assembly order reflects evolution , and flagellar assemply has the T3SS assembled before flagellum-specific parts like rod-hook-filament are added later.

I find this less than convincing. The rod-hook-filament structure is located on the outside of the cell, which presents the cell with an engineering problem, as the size of the structure precludes constructing it inside the cell and moving it outside. Instead, the rod-hook-filament is constructed in situ by proteins being transported through the hollow structure and added to the tip as it grows. Given that the TTSS plays a key role in the construction of the rod-hook-filament, it is only to be expected that it is assembled first.