another email that was caught and I am forwarding
Amy Lyn Edwards -- [log in to unmask]
Enterprise Applications Systems
Office of Information and Instructional Technology
University System of Georgia
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"There is nothing so powerful as truth,
- and often nothing so strange."
------------- Daniel Webster --------------
----------------- Original message (ID=52395F51) (229 lines) ------------------
From: "Lee Spencer" <[log in to unmask]>
To: "'Conchologists List'" <[log in to unmask]>
Subject: RE: hybrids
Date: Wed, 29 Jun 2005 17:44:40 -0400
In a biological sense, large scale hybridization at the population level is
termed reticulate evolution. It is reportedly common in some scleractinian
coral phylogenies, modern African cichlid fishes and some plant groups such
as oaks (see Veron 1996; Sylvester-Bradley 1977). I know of no reports of it
within the mollusks. At a lower scale, hybridization occurs among
individuals within different species populations, for example within
vertebrate groups such as the white-tailed and mule deer of North America
and also is some warbler groups, etc., but it occurs infrequently enough
that the species remain distinct. I am not sure of the scale your question
addresses.
>From a cladistic analysis point of view, hybridization at the reticulate
evolution scale is problematic since members of two presumably monophyletic
groups fuse to form a third group which may then be monophyletic afterwards.
It is a struggle with which I am currently dealing. Computer based character
analysis programs such as PAUP have no way to address whether or not a
reticulate event is more parsimonious. If anyone out there has any ideas on
how to address this issue, I would welcome them.
Lee Spencer
Veron, J. E. N. 1996. Evolution in corals, IN George D. Stanley, ed.
Paleobiology and biology of corals, The Paleontological Society Papers,
1:7-37. (ISSN 1089-3326)
Sylvester-Bradley, P. C. 1977. Biostratigraphical tests of evolutionary
theory, IN Erle G. Kauffman and Joseph E. Hazel, eds. Concepts and Methods
of Biostratigraphy, Dowden, Hutchinson & Ross, Stroudsburg, Penn. (ISBN
0879332468)
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<p class=3DMsoNormal><font size=3D2 color=3Dnavy face=3DArial><span =
style=3D'font-size:
10.0pt;font-family:Arial;color:navy'>In a biological sense, large scale
hybridization at the population level is termed reticulate evolution. It =
is
reportedly common in some scleractinian coral phylogenies, modern =
African
cichlid fishes and some plant groups such as oaks (see Veron 1996;
Sylvester-Bradley 1977). I know of no reports of it within the mollusks. =
At a
lower scale, hybridization occurs among individuals within different =
species
populations, for example within vertebrate groups such as the =
white-tailed and
mule deer of <st1:place w:st=3D"on">North America</st1:place> and also =
is some
warbler groups, etc., but it occurs infrequently enough that the species =
remain
distinct. I am not sure of the scale your question addresses. =
<o:p></o:p></span></font></p>
<p class=3DMsoNormal><font size=3D2 color=3Dnavy face=3DArial><span =
style=3D'font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=3DMsoNormal><font size=3D2 color=3Dnavy face=3DArial><span =
style=3D'font-size:
10.0pt;font-family:Arial;color:navy'>From a cladistic analysis point of =
view,
hybridization at the reticulate evolution scale is problematic since =
members of
two presumably monophyletic groups fuse to form a third group which may =
then be
monophyletic afterwards. It is a struggle with which I am currently =
dealing.
Computer based character analysis programs such as PAUP have no way to =
address
whether or not a reticulate event is more parsimonious. If anyone out =
there has
any ideas on how to address this issue, I would welcome =
them.<o:p></o:p></span></font></p>
<p class=3DMsoNormal><font size=3D2 color=3Dnavy face=3DArial><span =
style=3D'font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=3DMsoNormal><font size=3D2 color=3Dnavy face=3DArial><span =
style=3D'font-size:
10.0pt;font-family:Arial;color:navy'>Lee =
Spencer<o:p></o:p></span></font></p>
<p class=3DMsoNormal><font size=3D2 color=3Dnavy face=3DArial><span =
style=3D'font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=3DMsoNormal><font size=3D2 color=3Dnavy face=3DArial><span =
style=3D'font-size:
10.0pt;font-family:Arial;color:navy'>Veron, J. E. N. 1996. Evolution in =
corals,
IN George D. Stanley, ed. Paleobiology and biology of corals, The
Paleontological Society Papers, 1:7-37. (ISSN =
1089-3326)<o:p></o:p></span></font></p>
<p class=3DMsoNormal><font size=3D2 color=3Dnavy face=3DArial><span =
style=3D'font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=3DMsoNormal><font size=3D2 color=3Dnavy face=3DArial><span =
style=3D'font-size:
10.0pt;font-family:Arial;color:navy'>Sylvester-Bradley, P. C. 1977.
Biostratigraphical tests of evolutionary theory, IN Erle G. Kauffman and =
Joseph
E. Hazel, eds. Concepts and Methods of Biostratigraphy, Dowden, =
Hutchinson
& Ross, <st1:place w:st=3D"on"><st1:City =
w:st=3D"on">Stroudsburg</st1:City>, <st1:State
w:st=3D"on">Penn.</st1:State></st1:place> (ISBN =
0879332468)<o:p></o:p></span></font></p>
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style=3D'font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
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