pbs Digest, Vol 17, Issue 29

Alan Meerow miaam@ars-grin.gov
Sun, 20 Jun 2004 15:15:29 PDT
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.


 ----- 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
> 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
> 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
> 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
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