Reproducing early and often is the key to rapid evolution...( New Haven Conn. Yale researchers ha...)

New Haven, Conn. Yale researchers have harnessed the power of 21st century computing to confirm an idea first proposed in 1916 that plants with rapid reproductive cycles evolve faster. Their findings appear in the October 3rd edition of Science.

"Our study has profound consequence for the understanding of evolution made possible by the critical role of the computer in revealing major evolutionary patterns," said senior author Michael Donoghue, the G. Evelyn Hutchinson Professor of Ecology & Evolutionary Biology and Curator of Botany at Yale's Peabody Museum of Natural History

Long involved with the Tree of Life Web Project, which is attempting to reconstruct the "tree" representing the genealogical relationships of all species on Earth, Donoghue has spearheaded the study of flowering plant evolution. In animals, the variation in rate of molecular evolution has been ascribed to differences in generation time, metabolic rate, DNA repair, and body size; in plants, the differences have been more difficult to determine.

The current analysis evaluated DNA sequence data for five major evolutionary lineages within the flowering plants, comparing genetic markers in their chloroplast, nuclear, and mitochondrial genomes. The authors also employed new methods for making some of the largest phylogenetic trees ever built.

A clear pattern emerged. Plants with a shorter generation time from the time they germinate to the time that a seed they produce germinates generally show more rapid rates of molecular evolution. Longer-lived trees and shrubs, by contrast, evolve more slowly and show less variability in their rates of evolution. The study also showed that the difference in rate seen between herbs and woody plants has been maintained through evolutionary time.

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