Path: utzoo!attcan!uunet!lll-winken!lll-tis!ames!husc6!rutgers!orstcs!ucs.orst.edu!kramerj
From: kramerj@ucs.orst.edu (Jack Kramer - OSU Gene Res)
Newsgroups: sci.bio
Subject: cell origins
Message-ID: <5592@orstcs.CS.ORST.EDU>
Date: 20 Jul 88 01:12:18 GMT
Sender: netnews@orstcs.CS.ORST.EDU
Reply-To: kramerj@ucs.orst.edu (Jack Kramer - OSU Gene Res)
Organization: Oregon State University -- UCS
Lines: 48


Tried to followup on this before in response to a similar question but it
bounced.

I assume from your question you are asking about eukaryotic cells.  Lynn
Margolis has made this subject her life work and she is an excellent
author.  She has published several books.  They give a very
good popular literature level introduction to the subject.  She is very
strongly biased to her own theories but does give references so one can
branch out form there.

Her theories have become pretty much the paradigm in this area but there
is still a good deal of controversy especially when organelles
other than mitochondria and chloroplasts are considered.

I prefer an alternative hypothesis mentioned only a few time in the
literature but which makes much more sense to me than the Serial
Symbiosis hypothesis.  It seems much more probably to me that the 
first eukariotic cells evolved from obligate symbiotic agregates of
prokariotic cells.  The pro-mitochondria and pro-chloroplasts probably
formed the first such associations which are most justifiable on physical
and chemical grounds. The two or so billion years during which the 
prokariotes were the only form of cellular life is provides the long
times necessary.  the close coupling of the capture and use of
the sun's energy in photosynthesis and respiration would provide strong
selective pressure to maintain and optimize this relationship.  Cycles
like this can easily create spinoff eddies of energy which could then
be tapped to further enhance the association.  Eventual joining of the
group by the protonucleus then gave the addvantage of the eukariotic
genomeic apparatus.  the association became so advantageous that an
enveloping envolope evolved to protect and isolate the minimum group
of organelles.  A corallary to this is the possibility of several
origins of the eukariotic lineages.  Anyone tryuing to make sense out
of the phylogeny of unicellular eukariotes such as the algae, fungi
and protozoa should welcome this suggestion.

A couple of other anthologies are:
Origins and Evolution of Eukaryotic Intracellular Organelles
	Edited by Jerome Fredrick
The Origin of Eukaryotic Cells
	Edited by B D Dyer and R Obar

The origin of the prokaryotic and protoeukaryotic cells which evolved into 
the (controversially) more advanced and complex eukaryotic cells
is voluminously covered under the subject of prebiotic evolution.

Jack Kramer
kramerj@ucs.orst.edu
cmathews.kramer@bionet-20.arpa