word pictures in order to explain what
had been discovered. Their careful tute-
lage gave me the understanding of how
to pursue research projects. Because
my earliest training was in both botany
and zoology, it has been natural for me
to emphasize tests for common evol-
utionary patterns between plants and
animals that may reveal common under-
lying processes. This emphasis is
reflected both by the breadth of organ-
isms on which mystudents, post-doctoral
associates and I have worked (everything
from fruit flies to fungi and fruit bats to
Louisiana Irises) and the synthetic treat-
ments we have produced—e.g., the two
books Natural Hybridization and
Evolution, 1997 andEvolution Through
Genetic Exchange, 2006.(Re)Turning to PlantsThough, as indicated above, my
colleagues and I have examined many
types of organisms, 20 years ago I did
make a decision to focus most of my
research efforts on plant taxa. Several
factors led to this decision, two of
which related to my earliest training in
evolutionary botany and zoology. I
had learned quickly, that testing many
of the hypotheses in which I was
interested—especially those associated
with the processes of genetic exchange,
speciation and adaptation—required
taxa that would allow a dual approach
of experimental manipulations and
surveys of natural populations. Most
plant and animal groups (and for that
matter, many bacterial and viral assem-
blages) provide opportunities to
examine naturally occurring populations
for the purpose of estimating evolution-
ary processes such as genetic exchange
via introgressive hybridization and/or
lateral transfer. However, few animal
clades allow the type of direct assess-
ments possible in studies of plant
species (e.g. through reciprocal trans-
plantations into both experimental
and natural environments). In addition,my interest in testing the descrip-
tiveness of the web-of-life metaphor
(i.e., that emphasizes the importance of
genetic exchange in the evolution of
organisms) led me to choose plants
over animals. Thus, evolutionary biol-
ogists consider plants to be paradigms
of such processes as introgressive
hybridization, hybrid speciation and
adaptive trait transfers.Has Our Work Affected Plant
Biotechnology?I believe that the work carried out by my
colleagues and myself has impacted the
field of plant biotechnology in several
ways. However, all of the effects from
this work can likely be traced back to
our emphasis on studies of population
level phenomena. In the early 1990s,
when we began our research into reticu-
late evolution, plant evolutionary
biology was characterized by systematic
treatments (i.e., studies that defined the
relationships of species). Indeed, many
decades had passed since the appearance
of the wealth of publications by such
workers as Edgar Anderson and
Ledyard Stebbins on the population-
level phenomena associated with
genetic exchange between plant lineages.
With few exceptions—e.g., see many
publications of Verne Grant and Don
Levin—the study of plant evolution had
emphasized pattern over process. In con-
trast, our work was designed to empha-
size process over pattern. For example,
we have asked how the processes of intro-
gressive hybridization, hybrid speciation,
lateral exchange, and adaptive trait
transfer have affected the evolutionary
patterns reflected in present-day bio
diversity. This process-over-pattern
focus has led to the application of our
findings by plant biotechnologists,
particularly when they are considering
the effect that gene exchange might
have on development and control of
bio-engineered products. One example
of this can be seen in the interest that we44 MENDELIAN GENETICS AND PLANT REPRODUCTION