The modern, molecular hunt for the world’s biodiversity

Alvin made discoveries of life at depths that had never been visited before.
OAR/National Undersea Research Program (NURP); Woods Hole Oceanographic Inst, CC BY

For this kind of exploration, out of sight was truly out of mind. Until 1977, we had no idea the ocean floor was home to life at all, never mind rich communities including Lokiarchaeota. They were first discovered by the submersible Alvin – which wasn’t even looking for life. Its original mission was to study the ocean floor looking for evidence of plate tectonics. As well as finding evidence that the sea floors are spreading, Alvin sent back images of a rich new ecosystem of completely unknown species fueled entirely by chemical energy, instead of solar energy like all other ecosystems previously known.

A fact we now take for granted is that wherever we look for life, we find it, including concentrated acids, fluids as corrosive as floor stripper, in rock and kilometers beneath the Antarctic ice sheet. It can even survive in outer space (though of course we haven’t identified any non-Earth-originated life – yet).

Comparative DNA profiles of 14 people, obtained via PCR.
Wellcome Images, CC BY-NC-ND

Genetic fingerprints

But what’s amazing about the discovery of Lokiarchaeota is that no one has ever actually seen it. Everything we know about it is discovered by the new field of metagenomics, which allows us to extract fragments of DNA from the environment, read the sequence information and study it with computational techniques.

The starting point for metagenomic research can be anything, including feces, in the case of the human microbiome, or a sample of ocean sediment, in case of Lokiarcheota. Ultimately these genetic profiles are known to us only as an electronic string of 1’s and 0’s in —> Read More