Genome of Oldest Flowering Plant Sequenced
By sequencing the genome of a plant whose evolutionary lineage traces back to the last common ancestor of all flowering plants, scientists say they have found the answer to a question that so baffled Charles Darwin, he dubbed it the "abominable mystery."
The question is: why did flowers suddenly explode onto the scene some 160 million years ago? The answer, according to a series of studies published in the journal Science, is a so-called "genome doubling event" that appears to have taken place 200 million years ago. During it, an early ancestor of flowering plants gained a duplicate of its genome. Some of the duplicated genes disappeared as time went on, but others took on new functions - including ones that would have aided the development of floral organs, according to the researchers.
The flower at the center of all of this is the Amborella trichopoda, found only on the main island of New Caledonia in the South Pacific.
"In the same way that the genome sequence of the platypus - a survivor of an ancient lineage - can help us study the evolution of all mammals, the genome sequence of Amborella can help us learn about the evolution of all flowers," said Victor Albert, a biologist from the University at Buffalo who participated in the research. Thus, piecing its genome together has opened all kinds of doors that had previously remained close to scientists. Already, comparative analyses of the plant's genome are giving way to new perspectives on the genetic origins of traits in all flowering plants everywhere, including food crop species.
"This work provides the first global insight as to how flowering plants are genetically different from all other plants on Earth," said Brad Barbazuk, a biologist from the University of Florida said, "and it provides new clues as to how seed plants are genetically different from non-seed plants."
Doug Soltis, who also teaches biology at the Universtiy of Florida, said the study lays important groundwork for future research.
"Amborella had never been studied in any detail, so we started from scratch trying to put together this jigsaw puzzle of hereditary information by mixing methods that have never been used in combination before," he said. "Now we can assemble, sequence and evaluate complex genomes and answer fundamental biological questions."