pbs Digest, Vol 17, Issue 29
Alan Meerow (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.
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
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