RIESEBERG, LOREN H. Department of Biology, Indiana University, 1001 E. Third St., Bloomington, IN 47405. - Speciation: A legacy of botanical discovery.
Major botanical advances often suffer the worst of fates – the
scientific community ignores them until they are independently
"discovered" or confirmed by zoologists. For example, the
principles of inheritance, initially worked out in the garden pea,
were not generally accepted until verified in animals. Likewise, the
discovery of mobile genetic elements in maize by Barbara McClintock
was largely ignored until similar observations were made in bacteria,
yeast and flies. More recently, botanical claims for a prominent role
for major genes in adaptation were received with skepticism until
similar findings in animals prompted a reevaluation. A similar
rediscovery process is ongoing in the area of speciation. Zoologists
are finding that in animals, like plants, genomes are not as coadapted
as previously believed, and that species barriers often are porous.
They also are finding evidence that, like plants, speciation in
animals is primarily driven by divergent selection and that speciation
can take place in the presence of gene flow. Finally, evidence that
hybridization has played a significant role in animal evolution is
emerging, providing a complement to pioneering studies of plants.
This pattern of discovery indicates the need for botanists to play a
more prominent role in the ongoing intellectual debates in
evolutionary biology.
Key words: coadaptation, hybridization, selection, speciation