John Bryan
Wed, 24 Dec 2003 10:08:52 PST
Dear Jane;
Well said. Happy Holidays, Cheers, John E. Bryan

Jane McGary wrote:
> Mark McDonough's reaction to the proposed reorganization of the genus
> Scilla is similar to mine, though I had not thought about it in such
> detail. In addition to Allium, one can easily think of many other genera
> which display differences in, e.g., seed morphology similar to those
> offered as the basis of genus differentiation in "Scilla nova." Calochortus
> is a good example for seeds, and for bulb and root form Iris is obvious.
> There are anomalous bulbs or corms in many genera -- for example, there are
> a few stoloniferous species in Crocus, Fritillaria, and Lilium.
> I would like someone who actually does taxonomy based on DNA studies to
> clarify something for me. As I understand it, these studies are based on
> certain selected portions, or segments, of a few certain chromosomes -- not
> on the whole genome of the plant, which would not be feasible with present
> technology. How does the researcher know that the sequence(s) selected
> represent the variation in the entire genome in a meaningful and
> statistically reliable way?
> I am not a scientist, but linguists employ rather similar statistical
> analyses to estimate the degree to which various languages are related and
> the time depth of their divergence from common ancestors. One currently
> popular method, called mass comparison, is capable of generating extremely
> dubious results if done on a database that is not, shall we say, perfectly
> understood by those conducting the comparison.
> I think that quite a few of us on this forum have studied enough statistics
> and science to understand a brief answer to these questions, and we
> probably all have some grasp of genetics, so if someone appropriate has the
> time, would you please enlighten us?
> Thanks,
> Jane McGary
> Northwestern Oregon
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