The flagellum has 30 or so unique (non-homologous) proteins (Talk.Origins)
Evolutionists propose that irreducibly complex systems can arise by co-option of parts from other existing systems. But approximately thirty of the proteins needed for the bacterial flagellum are unique to it; closely similar proteins are not found in other living systems. Thus, there is apparently no place they could have been co-opted from.
- Minnich, Scott A., 2003. Unlocking the Mystery of Life (video), Illusta Media.
- Minnich, Scott A. and Stephen C. Meyer. 2004. Genetic analysis of coordinate flagellar and type III regulatory circuits in pathogenic bacteria. Second International Conference on Design and Nature,
(Talk.Origins quotes in blue)
1. The claim is simply false. Of the twenty proteins in the archetypal Salmonella bacterial flagellum which appear to be required in all bacterial flagella, only two have no known homologies, that is, are "unique".
While there are only twenty proteins common to all bacterial flagellum, when examined collectively there are thirty unique proteins spread among all bacterial flagellum. This makes Talk Origins argument a straw man.
It is at least plausible that homologies for those will be discovered later.
This is nothing short of an act of faith. When one has no evidence, it is always possible to say that it will be found someday.
At least nine flagellar proteins are homologous to proteins of the Type-III secretion system (T3SS), suggesting the two evolved from a common ancestor. Regardless, the existence of many homologous proteins shows that the parts of the flagellum can function for purposes other than motility
While the Type-III secretion system proteins are similar to these nine flagellar proteins, they are not identical, so the actual flagellar proteins only function for motion.
2. There is no such thing as "the" bacterial flagellum. There are thousands, perhaps millions, of varieties among different bacteria, not to mention other very different kinds of flagella on archaebacteria and eukaryotes. The Salmonella flagellum, for example, has 22 additional proteins which some other bacteria lack in their flagella.
This term bacterial flagellum refers specifically to the rotary type of flagellum and while there is some variety they all follow the same basic design.
Do design proponents suggest that each was a separate creation, or did they evolve?
Yes, it is possible that some of the variation, such the length of the flagellum, is a result of mutation, but such a factor has nothing to do with the irreducible complexity of the bacterial flagellum. However there is no reason why each variety of bacterial flagellum could not have been a separate creation.