Scilla
Jane McGary (Tue, 23 Dec 2003 10:38:20 PST)

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