impact of spores on evolution

fawolf at cc.usu.edu fawolf at cc.usu.edu
Sun Oct 15 06:35:43 EST 1995


In article <s2156974-1510951432380001 at 129.94.204.201>, s2156974 at cse.unsw.edu.au (Ruby Estrella) writes:
> Hi,
> I'm a 2nd year uni student studying microbiology 1 and I was wondering if
> anyone here is familiar with the article "Revival and Identification of
> Bacterial Spores in 25- to 40- MIllion Year-Old Dominican Amber" found in
> Science, May 1995? Well, this article describes the the discovery of
> ancient Bacillus spores in the gut of a bee in amber by scientists Cano
> and Borucki.  After analysis, they found this species to be closely
> related to a present day species, B.sphaericus. I was wondering how this
> is possible if the spores have been  dormant (and therefore not subjected
> to evolution) for millions of years and still share characteristics with
> B.sphaericus today?  Some would argue contamination, yet it was clear in
> the article that the scientists took special precautions to prevent that. 
> 
> I would also appreciate if anyone could guide me to related information
> leading to references  on bacterial spores, evolution/taxonomy and 
> phylogeny. 
> 
> thanks very much
> Ruby Estrella
> s2156974 at cse.unsw.edu.au

It depends what you (they) mean by "closely related". If B. spaericus is a
descendent of the amber spores then they might be more closely related,
interms of overall divergence than two extant species in the same genus.
If I remember correctly the paper used molecular differences (or perhaps 
not?) - but anyway, divergence between extant taxa is a function of 2 X
 the time since divergence (each taxon has a branch), whereas ancestor-
descendent differences are separated on only one branch at 1 x divergence
time.  Incorporating fossil data into phylogenetic analysis is likely
to become an exciting and challenging area.

Hope this answers the question, at least partly.

-- 
Paul Wolf
Utah State University, Logan
UT 84322, USA.
Email: wolf at cc.usu.edu



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