Genome Mapping Confirms Oldest Flowering Plant Is One of the Sexiest

Genome Mapping Confirms Oldest Flowering Plant Is One of the Sexiest

Genome mapping confirms that the oldest living species of flowering plant is still, without a doubt, one of the sexiest, as well as hungriest, around. Don’t blame it on the rain — blame it on the Amborella trichopoda’s organelles and mitochondrial DNA.

The Amborella trichopoda is a woody shrub with an ancient lineage. Its habitat is in the remote jungles of New Caledonia. The flowering shrub has consumed and has within it the genomes from the organelles of four different plants — one being a species of algae, and the other three being species of moss.

The new study about the varied appetites of the Amborella trichopoda and the genome mapping done of the species has been published in the journal Nature, and you can read it by clicking on the last source listed below.

What was behind the mystery of the sudden flourishing of flowering plants?

Scientists wanted to discover the answer to the mystery that puzzled even the great Charles Darwin — namely, why several hundred thousand species of flowering plants came into being and flourished on Earth around 200 million years ago.

It took scientists literally years to completely sequence the Amborella trichopoda’s entire genome, but doing so may have solved the mystery that puzzled Darwin and countless scientists who came after him.

Somehow, out of these hundreds of thousands of now extinct flowering plants, an ancestor of Amborella trichopoda survived to the present day.

A group of researchers called the Amborella Genome Project took it upon themselves to accomplish the genome mapping of this ancestor of Amborella trichopoda.

Some unknown “doubling event” caused the plant’s genome to double about 200 million years ago. This “doubling event,” the researchers theorize, might be what puzzled Darwin.

Mitochondrial sex behind the flowering plant’s hunger?

According to Jeffrey D. Palmer, an Indiana University evolutionary biologist and author of the mitochondrial DNA paper, the new study “will help bring mitochondrial sex out of the closet.”

Palmer added that the genome of the Amborella trichopoda is unique, because of the its “scale of horizontal DNA transfer.” It’s the only plant or organism of any kind discovered so far that has four genomes “taken up by horizontal transfer.”

What exposed A. trichopoda to foreign mitrochondrial DNA?

Many other plants grow around, or even on, the flowering shrub A. trichopoda, including algae and moss. The scientists of the Amborella Genome Project theorize that the shrub might have been exposed to foreign DNA through tears or cuts. The foreign DNA then might have somehow fused with the genomes of the A. trichopoda.

Palmer states that the behavior of the flowering shrub’s mitochondria is “a kind of sex” which is similar to that of “nuclear genomes.”

Though the Amborella trichopoda contains the entire genomes of four other plant species, it also contains the foreign DNA of two other plant species, making a total of almost six whole genomes existing within the genome structure of one plant.

The vast number of the plant’s genetic base pairs is another quality that makes A. trichopoda unique. Instead of its having the fairly typical number of mitochondrial genome base pairs, around 500,000, which most other plants have, Amborella trichopoda has an incredible 3.9 million base pairs.

The doubling of genomes has been seen before in animals like bony fishes, and even humans. According to Victor Albert of the University at Buffalo, “the genome sequence of Amborella can help us learn about the evolution of all flowers.”

According to the team of researchers, while some doubled genomes disappear over time, other ones take on functions like, in the case of flowering plants, the development of floral organs.

Biologist Doug Soltis of the University of Florida believes that the study is important in that it has provided important information for later research to build upon. With the knowledge of the entire genome sequence of Amborella trichopoda, according to Soltis, scientists can now “assemble, sequence and evaluate complex genomes and answer fundamental biological questions.”

The study published in Nature about the genome mapping of Amborella trichopoda confirms that besides being one of the oldest species of flowering plants, this flowering shrub is also one of the sexiest and hungriest plants ever discovered.

Written by: Douglas Cobb
Nature journal article

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