From: Derek Gatherer (d.gatherer@vir.gla.ac.uk)
Date: Mon 14 Nov 2005 - 14:52:33 GMT
At 19:05 11/11/2005, Dace wrote:
>causation based on contact mechanics. This attitude cropped up again in the
>news recently when it was reported that a small number of Arabidopsis
>thaliana plants had mysteriously reverted to the genes of its grandparents
>in place of the mutant genes of its parents. All the mutations of their
>parents had been repaired, as if they'd been descended directly from their
>wildtype grandparents. Researchers were baffled as to how the plants knew
>what the pre-mutant genetic sequences were. They then concluded that there
>must be a complete copy of the plant's genes contained in its RNA, and it
>was from this copy that the numerous, disparate mutations in its genome were
>repaired. Now, there's no evidence that RNA contains any genes at all, much
>less a complete set of them. Whether or not the researchers are correct,
>they're making an awfully big assumption. Both Scientific American and
>Science reported it as a done deal: there must be another copy of the genome
>in RNA. No evidence, just blind allegiance to reductionistic metaphysics.
>Of course, it's just as likely that the wildtype reversion is based on
>holistic memory, but the cult of reductionism doesn't allow for this
>possibility.
I think you must be referring to the papers in Nature (March and Sept)
was the first one. Actually the reversions were in a pair of loci,
not the whole genome. There are a couple of possible explanations, eg:
gene conversion:
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=16136081î«
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=16136082î«
or toxic mutator and selection:
The back-transcription from RNA theory and the 2 alternative theories
are all perfectly plausible in terms of known biochemical
mechanisms. It's just a question of which, if any, is the correct
one - the answer to which will be obtained by standard laboratory
investigation. No need for any theories requiring us to abandon the
world as we currently know it.
===============================================================
This was distributed via the memetics list associated with the
Journal of Memetics - Evolutionary Models of Information Transmission
For information about the journal and the list (e.g. unsubscribing)
see: http://www.cpm.mmu.ac.uk/jom-emit
This archive was generated by hypermail 2.1.5 : Mon 14 Nov 2005 - 15:12:09 GMT