Genome of Oldest Flowering Plant Sequenced

[muriel_volestrangler]

3. Yeah; the point is that most other flowers have a more recent last common ancestor

This one is an 'outsider' - hence the reference to the platypus. Here's what the group says:

Amborella (Amborella trichopoda) is unique as the sole survivor of an ancient evolutionary lineage that traces back to the last common ancestor of all flowering plants. The plant is a small understory tree found only on the main island of New Caledonia in the South Pacific. An effort to decipher the Amborella genome -- led by scientists at Penn State University, the University at Buffalo, the University of Florida, the University of Georgia, and the University of California-Riverside -- is uncovering evidence for the evolutionary processes that paved the way for the amazing diversity of the more than 300,000 flowering plant species we enjoy today.

This unique heritage gives Amborella a special role in the study of flowering plants. "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 of the University at Buffalo.
...
Jim Leebens-Mack from UGA noted that "The Amborella genome sequence facilitated reconstruction of the ancestral gene order in the 'core eudicots,' a huge group that comprises about 75 percent of all angiosperms. This group includes tomato, apple and legumes, as well as timber trees such as oak and poplar." As an evolutionary outsider to this diverse group, the Amborella genome allowed the researchers to estimate the linear order of genes in an ancestral eudicot genome and to infer lineage-specific changes that occurred over 120 million years of evolution in the core eudicot.

At the same time, Amborella seems to have acquired some unusual genomic characteristics since it split from the rest of the flowering plant tree of life. For example, DNA sequences that can change locations or multiply within the genome (transposable elements) seem to have stabilized in the Amborella genome. Most plants show evidence of recent bursts of this mobile DNA activity, "But Amborella is unique in that it does not seem to have acquired many new mobile sequences in the past several million years," stated Sue Wessler of the University of California-Riverside. "Insertion of some transposable elements can affect the expression and function of protein-coding genes, so the cessation of mobile DNA activity may have slowed the rate of evolution of both genome structure and gene function."

http://www.amborella.org/