You raise a good point, esp. with Hymenocallis, where reticulation is a very real possibility, and ideally, one would want a chloroplast sequence phylogeny as well (uniparental inheritance). Unfortunately, so far none provides any resolution at all. In addition to the paper to which you provide a link, Lucinda Mcdade published some interesting papers on reticulation and cladistics, mostly if not entirely on reconstructions based on morphological data. Alan ----- Original Message ----- From: <ConroeJoe@aol.com> To: <pbs@lists.ibiblio.org> Sent: Sunday, June 20, 2004 4:54 PM Subject: [pbs] Re: pbs Digest, Vol 17, Issue 29 > In a message dated 6/20/2004 2:38:57 PM Central Daylight Time, > pbs-request@lists.ibiblio.org writes: > > > The preliminary data that we have based on ITS sequences show two > > migrations > > out of Mexico... Interestingly, H. glauca (one of my > > favorite Mexican species) is sister to the other two Mexican clades. > > > > Hi, > > Nice work I'm sure, I've read some of your manuscripts and they are well > done, and -well-thought-out. > > I've got to ask how you know that only tree branching occurred (clades), > rather than reticulate branching (fusions) as well. The clades-only approach is > inconsistent with the evolution of some plant species and I've been trying to > understand how this issue is finessed or directly addressed, as opposed to > sidestepped. So far I think I've mostly confused myself. > > When I've looked at single genes, it is easy enough to see proper clades. > Recombination doesn't clutter the picture too much within a cistron. But whole > genomes present another picture altogether. Hybridization events have > produced some genomes that are fusions of clades and not bifurcations. > > Perhaps reticulation (where it occurs) only limits precision, while still > allowing easy identification of major migrations? > > > > Conroe Joe > > LINKS: > > Reconstructing Reticulate Evolution in Species > http://cs.utexas.edu/users/nakhleh/… > > Journey Into the World of Cladistics (if you dare) > http://www.ucmp.berkeley.edu/clad/clad1.html > > _______________________________________________ > pbs mailing list > pbs@lists.ibiblio.org > http://www.pacificbulbsociety.org/list.php >