Flagellin and Tubulin Genes

Jerry Learn learn at u.washington.edu
Thu Oct 9 00:25:39 EST 1997


In article <61h4rc$g5e at net.bio.net>, Brian Foley <btf at t10.lanl.gov> wrote:

> Bob Cooper wrote:
> > 
> > Hi
> > 
> > I had a student question about genes that code for tubulin and
> > flagellin.  The flagella of prokaryotes and eukaryotes are analogous
> > structures.  Prokaryotic flagella are composed of flagellin subunits
> > while the microtubules that make up the eukaryotic flagellum
> > (undulopodium) are composed of tubulin.  Does anybody know if the genes
> > that code for these protein subunits (i.e., flagellin and tubulin) are
> > at all homologous?
> > 
> > Bob Cooper
> > rac7 at erols.co
> 
>         First of all, the word "homologous" is supposed to mean
> "derived from a common ancestor".  And this is usually a yes or
> no answer.  There are not supposed to be differeing levels of
> "homology".  However, people mis-use these terms in place of 
> "similar" and and "similarity" so much, that I suppose we need 
> to give up on the orignal definition.
> 

Brian,

Here I go being orthodox again, but I have to disagree.  I don't think we
should give up on the evolutionary definition of "homologous," just
because people misuse the word.  There is a useful distinction between the
two, as you point out.  I guess I will continue to try gently to correct
people (mainly molecular biologists) when they misuse the words homology
and homologous.

Jerry Learn

Research Associate

Health Sci. Ctr., Rm. K443-C      |
Dept. of Microbiology             | Learn at u.washington.edu
University of Washington          | Phone: (206) 616-4286
Box 357740                        |   FAX: (206) 616-1575     
Seattle, WA  98195-7740  USA      |   




More information about the Mol-evol mailing list