Analyzing the genome, meaning all the genetic material, of plankton samples collected in all Earth’s seas by the so-called scientific expedition Tara Oceans at the end of its world tour in 938 days, it is the task of researchers from Genoscope, the French national center for sequencing under the CEA. Composed of drifting organisms such as animals, plants, algae, viruses and bacteria, the plankton represents 80% single-cell organisms appeared on Earth 2.7 billion years ago. And, above all, it plays a crucial role in Earth’s main biogeochemical cycles (oxygen, carbon and nitrogen). That is to say the importance to know how planktonic populations reacts to climate changes.
In this context, “we have built a first catalogue of genes coming from 441 specimens collected by 68 sampling stations (out of the 210 realized during the whole expedition) located in the Atlantic, Pacific, Antarctic and Indian oceans, as well as in Mediterranean and in the Red Sea”, Éric Pelletier, researcher at Genoscope, said. This catalogue has been progressively implemented: it records today 117 million genes, of which only a little bit more than 47% present some similarities with already known proteins. 8 million core hours were necessary in 2015 on the supercomputer Curie to perform these comparisons.
By characterizing DNA and messenger RNA (used for protein synthesis) present in the specimens, the scientist intends to get a genomics description of what they contain but also the function of each of their genes and of the impact of their environment. “It is the first time that the metagenomics of these particular species is being done at such a scale”, the researcher added.
The results of this work has been published in Science in 2015 and an article is under preparation for Nature.
Graphic representation of the genes recorded.