In article <volker.knoop-1206961143180001 at g2.biologie.uni-ulm.de>, volker.knoop at biologie.uni-ulm.de (Volker Knoop) writes:
|> > I am not aware of any grand consensus about
|> > the origin, original function...
|>|> No, definitely no consensus. What I consider a good working hypothesis is
|> that autocatalytic introns of group I and group II arose in bacteria
|> rather early by chance and may really be considered as selfish sequences.
|> The endosymbiontic bacterial predecessors of mitochondria and chloroplasts
|> may have imported them into the eukaryotic cell. (These introns are
|> present in mitochondria and chloroplasts!!) Group II introns may have
|> invaded the nucleus and have evolved into what you today find as typical
|> eukaryotic spliceosomal introns.
|> Now these latter may indeed have gained later certain functions for
|> example having enhancer functions or by allowing for different products to
|> be made from a single gene via alternative splicing. Exon shuffling is
|> certainly another idea for ascribing function to introns but not so
|> popular any more.
|> Volker Knoop (volker.knoop at biologie.uni-ulm.de)
|> Allgemeine Botanik, Universitaet Ulm, D-89069 Ulm, Germany
|> phone +49-731-502-2615 fax -2626
Any pointers to some recent relevant literature? We have come across a Group I intron in a green algal 18S rDNA more or
less by accident and are intrigued by its possible function and evolutionary origin.
H.J. Sluiman (h.sluiman at rbge.org.uk)
Royal Botanic Garden Edinburgh
20A Inverleith Row
Edinburgh EH3 5LR
0131 4590446 x258