Tree of life for flowering plants reveals relationships among major groupsNovember 27, 2007AUSTIN, Texas-The evolutionary Tree of Life for flowering plants has been revealed using the largest collection of genomic data of these plants to date, report scientists from The University of Texas at Austin and University of Florida. The scientists, publishing two papers in Proceedings of the National Academy of Sciences this week online, 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. Robert Jansen, professor of integrative biology at The University of Texas at Austin, said the work sets the stage for all future comparative studies of flowering plants. "If you are interested in understanding the evolution of flowering plants, you can't do that unless you understand their relationships," said Jansen. The University of Florida team, led by Doug and Pam Soltis, 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, curator at the university's Florida Museum of Natural History. "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." The details of the flowering plants' rapid diversification have remained a mystery since Charles Darwin first suggested their evolutionary history is an "abominable mystery." "One of the reasons why it has been hard to understand evolutionary relationships among the major groups of flowering plants is because they diversified over such a short time frame," said Jansen. But by analyzing DNA sequences from completely sequenced chloroplast genomes, the scientists brought some clarity to the evolutionary picture. Jansen and his colleagues at The University of Texas at Austin analyzed DNA sequences of 81 genes from the chloroplast genome of 64 species of plants, while the Florida researchers analyzed 61 genes from 45 species. The two groups also performed a combined analysis, which produced evolutionary trees that included all of the major groups of flowering plants. As for the diversification's cause, it remains mysterious, Pam and Doug Soltis said. It's possible it was spurred by some major climatic event. It's also possible that a new evolutionary trait -a more efficient water-conducting cell that transfers water up plant stems-proved so effective that it spurred massive plant growth. This cell type is not present in the first three flowering plant lineages, said Doug Soltis, professor of botany at Florida. University of Texas at Austin |
|||||||||||||||||||||
| Related Flowering Plants Current Events and Flowering Plants News Articles In the war between the sexes, the one with the closest fungal relationship wins The war between the sexes has been fought on many fronts throughout time-from humans to birds to insects, the animal kingdom is replete with species involved in their own skirmishes. Common weed could provide clues on aging and cancer A common weed and human cancer cells could provide some very uncommon details about DNA structure and its relationship with telomeres and how they affect cellular aging and cancer, according to a team led by scientists from Texas A&M University and the University of Cincinnati (UC). Secrets in a seed: Clues into the evolution of the first flowers Approximately 120-130 million years ago, one of the most significant events in the history of the Earth occurred: the first flowering plants, or angiosperms, arose. Genome duplication responsible for more plant species than previously thought Extra genomes appear, on average, to offer no benefit or disadvantage to plants, but still play a key role in the origin of new species, say scientists from Indiana University Bloomington and three other institutions in this week's Proceedings of the National Academy of Sciences. Ferns took to the trees and thrived As flowering plants like giant trees quickly rose to dominate plant communities during the Cretaceous period, the ferns that had preceded them hardly saw it as a disappointment. CU-Boulder study shows 53 million-year-old high Arctic mammals wintered in darkness Ancestors of tapirs and ancient cousins of rhinos living above the Arctic Circle 53 million years ago endured six months of darkness each year in a far milder climate than today that featured lush, swampy forests. The evolutionary foundation of genomic imprinting in lower vertebrates A Chinese scientist group working in College of Life Science, Zhejiang University, has shown that, as mammalian Igf2 CpG island, goldfish Igf2 CpG island has a parental differentially methylated region (DMR). Coffee cultivation good for diversity in agrarian settlements but not in forests Coffee shrubs, both in themselves and because they are most often cultivated in the shade of large trees, can have a positive impact on plant and animal diversity in those parts of the landscape that are deforested and dominated by agriculture. Protea plants help unlock secrets of species 'hotspots' New species of flowering plants called proteas are exploding onto the scene three times faster in parts of Australia and South Africa than anywhere else in the world, creating exceptional 'hotspots' of species richness, according to new research published today in Proceedings of the National Academy of Sciences (PNAS). Plants grow bigger and more vigorously through changes in their internal clocks Hybrid plants, like corn, grow bigger and better than their parents because many of their genes for photosynthesis and starch metabolism are more active during the day, report researchers from The University of Texas at Austin in a new study published in the journal Nature. More Flowering Plants Current Events and Flowering Plants News Articles |
|||||||||||||||||||||
|
|||||||||||||||||||||
|
|||||||||||||||||||||