Martijn Huynen wrote:
>> Hi, I am looking for references that give the estimated "time of
> divergence" of the presently completely sequenced (and publicly
> available) Bacteria and Methanococcus janaschii. (so not only between
There are no reasonable biological data from which to estimate this--
macromolecular sequence data simply aren't sufficient to narrow
the date significantly within the range of reasonable estimates
allowed by fossils and geochemical evidence. Archaebacteria and
eubacteria could have diverged as early as
4 BYA or as recently as just 2 BYA. Some people argue that
3.8-BY-old stromatolites represent members of the eubacterial group
cyanobacteria, and that archaebacteria must have already been
a distinct lineage at any point in time when the distinctive
features of cyanobacteria had already arisen. Personally I think
this is a reasonable but somewhat risky argument. I'm guessing
that the answer is 3.5 +/- 0.5 BYA, but it might be safer to
assume 3 +/- 1 BYA.
I was very impressed with the computer model of RNA evolution
described in your PNAS paper of last year as well as in a more
recent paper. Some of us here are trying in much less sophisticated
ways to wrestle with the relationship between neutral evolution
and biological complexity. Soon I will be submitting a manuscript
about the possibility of constructive neutral evolution, a draft
of which is available at my web site:
http://is.dal.ca/~arlin/cne
I would appreciate any comments you might have. My approach to
evolution is very much based on the biochemical details of specific
life processes. So far I have not tried to make any connections with
systems theory, but I am interested in such connections, if they
exist. Regards,
Arlin
--
Arlin Stoltzfus, Ph.D.
Department of Biochemistry
Dalhousie University
Halifax, Nova Scotia B3H 4H7 CANADA
(email) arlin at is.dal.ca
(phone) 902-494-2968
(fax) 902-494-1355
