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The Evolution of Eukaryotic Cilia and Flagella as Motile and Sensory Organelles

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nickm...@gmail.com

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Sep 24, 2006, 10:03:53 PM9/24/06
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Check this out:

http://www.eurekah.com/abstract.php?chapid=2875&bookid=215&catid=20
=========================================
Chapter:
The Evolution of Eukaryotic Cilia and Flagella as Motile and Sensory
Organelles
David R. Mitchell

in: Origins and Evolution of Eukaryotic Endomembranes and Cytoskeleton,
edited by Gáspár Jékely. Š2006 Eurekah.com.

Eukaryotic cilia and flagella are motile organelles built on a scaffold
of doublet microtubules and powered by dynein ATPase motors. Some
thirty years ago, two competing views were presented to explain how the
complex machinery of these motile organelles had evolved. Overwhelming
evidence now refutes the hypothesis that they are the modified remnants
of symbiotic spirochaete-like prokaryotes, and supports the hypothesis
that they arose from a simpler cytoplasmic microtubule-based
intracellular transport system. However, because intermediate stages in
flagellar evolution have not been found in living eukaryotes, a clear
understanding of their early evolution has been elusive. Recent
progress in understanding phylogenetic relationships among present day
eukaryotes and in sequence analysis of flagellar proteins have begun to
provide a clearer picture of the origins of doublet and triplet
microtubules, flagellar dynein motors, and the 9+2 microtubule
architecture common to these organelles. We summarize evidence that the
last common ancestor of all eukaryotic organisms possessed a 9+2
flagellum that was used for gliding motility along surfaces, beating
motility to generate fluid flow, and localized distribution of sensory
receptors, and trace possible earlier stages in the evolution of these
characteristics.
=========================================

Free PDF online:
http://www.upstate.edu/cdb/mitcheld/publications/Jekey_Mitchell.pdf

Mitchell has now caught on to Cavalier-Smith's 1987 idea (the cilium
was derived from the mitotic spindle), although I don't think he cites
the article, which was either:

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed&cmd=Retrieve&dopt=AbstractPlus&list_uids=3113314&query_hl=42&itool=pubmed_docsum

...or...

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed&cmd=Retrieve&dopt=AbstractPlus&list_uids=3454290&query_hl=42&itool=pubmed_docsum


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