Interplay between genes and viruses in tiny ocean plankton

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Prochlorococcus, the sea’s most abundant plankton species.
Credit: Claire Ting, Department of Biology, Williams College

“New evidence from open-sea experiments shows there’s a constant shuffling of genetic material going on among the ocean’s tiny plankton… The research is uncovering a new facet of evolution and helping scientists see how microbes exploit changing conditions, such as altered light, temperature and nutrients.

The distributors or carriers of new genes, the scientists suspect, are the massive numbers of viruses also known to exist in seawater. Some of them are adept at infecting ocean microbes like Prochlorococcus, the sea’s most abundant plankton species. [All Prochlorococcus strains are very closely related, yet they display an array of physiologies and genetic diversity.] The ocean viruses, which carry their own genes as well as transport others, provide a way of transferring genes from old cells into new ones.”

    In an ocean habitat, the exchange of genetic material offers marine microbes a wide range of potential gene combinations, each of which might be best suited for a particular environment — which would allow the overall population to persist despite complex and unpredictable environmental changes.

The researchers are trying to learn how the microbes function as a system in which they have co-evolved with each other, and with the chemistry and physics of the oceans.