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 > > _______________________________________________ > pbs mailing list > pbs@lists.ibiblio.org > http://www.pacificbulbsociety.org/list.php