DNA of Oldest Flowering Plant Solves Darwin's Evolution Mystery
One of Darwin's mysteries may have been solved thanks to the sequenced genome of the Amborella plant. Scientists have discovered why flowers suddenly proliferated on Earth millions of years ago. In fact, the newly sequenced genome sheds new light on a major event in the history of life on Earth.
Amborella trichopoda is the sole survivor of an ancient evolutionary lineage that traces back to the last common ancestor of all flowering plants. It's a small understory tree that can be 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 study the evolution of all flowers," said Victor Albert, one of the researchers, in a news release.
So what did they find by sequencing this planet's genome? It turns out that the ancestor of all flowering plants, including Amborella, evolved following a "genome doubling event" that occurred about 200 million years ago. Some duplicated genes were lost over time but others took on new functions, including contributions to the development of floral organs.
In fact, this genome doubling may explain one of Darwin's mysteries--the apparently abrupt proliferation of new species of flowering plants during the Cretaceous period. It gives researchers further insight into the process of evolution as a whole.
"This work provides the first global insight as to how flowering plants are genetically different from all other plants on Earth," said Brad Barbazuk, one of the researchers, in a news release. "And it provides new clues as to how seed plants are genetically different from non-seed plants."
That's not all the researchers found, though. The newly sequenced genome also helped reconstruct the ancestral gene order in the "core eudicots." This huge group comprises about 75 percent of all angiosperms, including species like tomato, apple and legumes.
It's likely that the findings will continue to open up new discoveries, as well. Researchers are likely to learn more about the process of evolution and plants as a whole with this latest research.
The findings are published in the journal Science.