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Hey Judith,
This is great! Yeah, I'll
admit it. I did not know that chloroplasts had their own DNA. After
seeing your post I immediately googled chloroplast and see that apparently they,
like mitochondria, are bound by two membranes. I think it is intuitively
obvious that both chloroplasts and mitochondria were once free-living entities,
who then formed a symbiotic relationship with the cells that they now
inhabit. A very tight symbiosis indeed. It seems to me that
it can be very difficult to distinguish 'communal' from
'systemic'.
What an incredible choreography must take place
within eukaryotic plants! They are coordinating the activity of, count
them, three sets of DNA. What do we call them, mitchodrial, somatic,
and chloroplastic DNA? Not only can symbiosis be a driving force in
evolution Jerry, but cooperative structures are what allow life to exist at
all. I seem to remember that a brilliant man also said the
same!
Fantastic, thanks Judith.
David
P.S. Ha! ha! John! Ha! ha!
----- Original Message -----
Sent: Tuesday, August 23, 2005 12:54
PM
Subject: Another gem from the
library...
Last evening, I found another book, while sorting through my
father's reference library, that I decided to skim through and had
another revelation. The book is "The Lives of a Cell; Notes of a Biology
Watcher" By Lewis Thomas. This isn't your usual biology book on cells! The
contents lists the following as chapters:
The Lives of a Cell
Thoughts for a Countdown
On Societies as Organisms
A Fear of Pheromones
The Music of This Sphere
An Earnest Proposal
The Technology of Medicine
Vibes
Ceti
The Long Habit
Antaeus in Manhattan
Autonomy
Organelles as Organisms
Germs
Your VeryGood Health
Social Talk
Information
Death in the Open
Natural Science
Natural Man
The Iks
Computers
The Planning of Science
Some Biomythology
On Various Words
Living Language
On Probability and Possibility
The World's Biggest Membrane
What got me, in a big way, was the discussion on organelles. I've
posted quite often on the subject of mitochondrial DNA (mtDNA)here and my
bafflement on why medical science isn't studying the relations between
mitochondrial DNA and nuclear DNA, with an eye towards disease pathology
resulting from a dysfunction in this relation, etc.
Well, Lewis Thomas began talking about chloroplasts-- the
organelles in all plant cells which are responsible for photosynthesis.
Specifically, he discussed the fact that chloroplasts have their own DNA as
well!!! (ctDNA) I have never heard anything about DNA in chloroplasts prior to
this, and I'm into plants in a big way. So this was an amazing
discovery for me, which I have been researching ever since.
I was wondering if I'm the only one, on the list, who never heard
about this before? (Would you guys admit it???)
Judith
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