7 August 2007

Metagenomics for species discovery aboard the Beagle

Metagenomics, one of the two genome era tools that will be deployed aboard the replica Beagle, can help us discover not only new species, but even whole new genera.

Case in point: the recent discovery, reported in Science, of a bacteria named Candidatus Chloracidobacterium (Cab.) thermophilum in hot springs in Yellowstone National Park (aerial photo from Earth from Above by Yann Arthus-Bertrand).

Not only is Cab. thermophilum a new species but it is also distinct enough from other relatives to warrant classification as the founding member of a new genus. In mammalian terms that would be like discovering a major new branch of great apes on the same hierarchical level as humans (genus name Homo), gorillas (genus name Gorilla), chimpanzees (genus name Pan) and orangutans (genus name Pongo).

The investigators collected mixed samples from microbial mats in three different Yellowstone hot springs. The resulting grab-bag of DNA was analysed and sorted by computer into the genomes of individual species. One of their most exciting discoveries was this uniquely light-harvesting (photosynthetic) species of the Acidobacteria phylum.

While plants are the best known photosynthetic organisms, bacteria actually account for half the photosynthesis taking place on Earth. But only five of the 25 major bacterial phyla were known to have members with this ability. This discovery in Yellowstone brings that number up to six.

“The microbial mats give the hot springs in Yellowstone their remarkable yellow, orange, red, brown and green colors,” says Don Bryant of Penn State University. Yellowstone’s hot springs “house a diversity of microorganisms, but many are difficult or impossible to grow in the lab. Metagenomics has given us a powerful new tool for finding these hidden organisms and exploring their physiology, metabolism, and ecology."

“This is an excellent example of how metagenic information reveals how little we know about life on Earth,” said Ronald Weiner, program director in NSF’s Division of Molecular and Cellular Biosciences.

Metagenomics will be one of the central science projects on the new Beagle, promising discoveries of many new species, and maybe even new genera and families, on her repeat of the 1831-6 circumnavigation.

Thanks to Lockergnome of Tech News Watch for the tip off.

1 comment:

Richard Carter, FCD said...

I never meta genome I didn't like.