you wrote:
> >From my understanding, however, tissue
> >culture, although it produces a
> high degree of uniformity, is not *completely*
> "fool-proof" in producing all clones; some
> degree of mutation does occur.
Unfortunately that s true. However it s in the hand of the propagator to
minimize this risk.
In former times e.g. orchids were propagated in enormous amounts via
callus culture. People did not realize that such a callus (in fact some
kind of a plant-tumor) gives rise to some kind of micro-evolution on a
cellular level. That means the fastest growing cells (often due to
mutations!) have an advantage over slower (non mutated cells) and sooner
or later overgrow the culture. The same happens in human cancer by the
way, where cells collect mutations in a similar fashion.
Modern propagation setups mostly do not go via callus but via axillar
branching. This lowers the output of plants but dramatically reduces the
danger of introducing mutations.
Another means of keeping mutations low are slow growth cultures of stock
material which is set aside and kept on minimal medium to keep growth (=>
and mutation rate) as low as possible.
All the best
Andreas
Andreas Wistuba
Mudauer Ring 227; 68259 Mannheim; Germany
Tel.: +49 621 705471 Fax: +49 621 711307
e-mail: a.wistuba@carnivor.rhein-neckar.de
a.wistuba@dkfz-heidelberg.de
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