DNA Etc.

Kevin D. Preuss hyline@tampabay.rr.com
Thu, 13 Jan 2005 05:31:19 PST
Once in the company over lunch Nobel Peace Prize winner, Norman Borlaug put
it best by telling me, an aspiring taxonomist who was working with genetic
transformation/transgenic cereal grains at the time  (about ten years ago):

"There are some answers to nature we will never have"... and the we will
never have the entire answers to genetic codes figured out; like missing
pieces of a puzzle.

Having studied only one genus in depth and a few others superficially and
somewhat following the literature, although not keeping truly current, I
agree that even if you study at the population level or species level, or
even generic level there are unresolved relationships.

The there are those entities that are extinct....inferring relationships
here is dangerous.

All that said, I am a student of cladistics, the most modern approach to
John appears to be a backer of the Phentic approach, which was the initial
systems used by those like Adanson and Herbert.

I think that there a need for both.  It comes down to scientific
communication.  The horticultural world needs to know the name of a plant
and what group it belongs to, human nature too classify.  Scientists need to
know the evolutionary implications to classify.

classification is artificial anyway....a construct of man's mind.  these
barriers are changing throughout time.

blah blah blah...

Kevin Preuss

----- Original Message ----- 
From: "James Frelichowski" <thisisnotgonnawork@yahoo.com>
To: "Pacific Bulb Society" <pbs@lists.ibiblio.org>
Sent: Wednesday, January 12, 2005 8:55 PM
Subject: Re: [pbs] DNA Etc.

> DNA markers are a beast of their own also.  We need to ascribe them to
genes and genetic changes that lead to speciation.  The effects of selection
and the environment on plant development are another twist to the story so
differences in physical aspects of the plant are still invaluable to the
study of plants.  Sometimes the polymorphism based on molecular markers can
mutant in either direction and lead to convergent similarities among
different genotypes or random difference in genotypes that should be similar
by descent.  Speciation is caused by so many factors that there is no time
here to list them all.  Studying the DNA is a small part of the whole as
many samples are needed to see the frequency differences in populations.  We
should target DNA markers to document the leaps and bounds that lead to
speciation or irreversible (or slowly reversible) fingerprints left in the
genome that gets passed on to the lineage.  Another reason to keep the
classification based on morph
>  ological
>  markers, DNA marker technology is expensive to start up, but I am the
beneficiary of it, so let us have our cake and eat it too and use both
> James Frelichowski
> John Bryan <johnbryan@worldnet.att.net> wrote:
> Dear Lee Poulsen:
> I agree 100% with you. No one can deny the valuable contributions the
> study of DNA can make. But that such upsets the composition of genera,
> as we know them, and have known them for years, is, in my opinion, a
> step in the wrong direction.
> If differences are not visible with a 10 x hand held lens, then I
> question the usefulness of the studies. Surely the objective is, and
> should be, the identification of a plant.
> Technology marches on, I am sure there will come a day when DNA samples
> are found not to be the end of advancements in our knowledge of plants.
> The nomenclature that has, and still does serve us well, should be,
> again in my opinion, preserved. In my opinion, the new classification of
> genera and species, should form a basis of a new and separate
> classification, it should be recognized and be available to those who
> would profit from such knowledge, such as breeders of the various
> genera.
> Is it not time, as progress is made, but before we destroy the
> nomenclature that has served us so well, to consider another record of
> such determinations, separate but hand in hand with that existing. Such
> being available to those who can take advantage of recent
> determinations, but not to the point of reclassification, and the
> casting aside of tried and true divisions, based on DNA. I often wonder
> just how many DNA samples are taken to assure conclusions reached are
> indeed correct. Are, as an example, studies made of the DNA of the same
> species from different geographic locations? Do clones of a species
> vary?
> Thank you for your comments, I agree with you. Cheers, John E. Bryan
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