Sunday, December 02, 2007

Major Plant Diversification < 5 Million Years Ago

Using plastid genome-scale data to resolve enigmatic relationships among basal angiosperms. 2007. M.J. Moore et al., PNAS early on-line pub.

Phylogenetic relationships among the major lineages of flowering plants based on plastid genome sequences. Pictured counter-clockwise from the root at the base of the circle tree are: Amborella trichopoda, Nymphaea odorata, Illicium floridanum, Chloranthus angustifolius, Piper longum, Liriodendron tulipifera, Ceratophyllum demersum, Ranunculus ficaria, Pelargonium exstipulatum, Helianthus annuus, Yucca filamentosa, Triticum aestivum, and Acorus americanus. New Caledonia, home to Amborella trichopoda, is shown in the background. credit: Gwen Gage

From the press release:

The evolutionary Tree of Life for flowering plants has been revealed using the largest collection of genomic data of these plants to date. Scientists found that the two largest groups of flowering plants, monocots (grasses and their relatives) and eudicots (including sunflowers and tomatoes), are more closely related to each other than to any of the other major lineages.

The analyses also confirmed that a unique species of plant called Amborella, found only on the Pacific island of New Caledonia, represents the earliest diverging lineage of flowering plants.

The University of Florida team also showed that the major diversification of flowering plants, so stunning that the researchers are calling it the “Big Bang,” took place in the comparatively short period of less than five million years. This resulted in all five major lineages of flowering plants present today.

“Flowering plants today comprise around 400,000 species,” said Pam Soltis. “To think that the burst that gave rise to almost all of these plants occurred in less than five million years is pretty amazing—especially when you consider that flowering plants as a group have been around for at least 130 million years.”