Giant Viruses

[Recusant]

Sounds scary, but they mostly spend their time with amoebae and algae rather than with animals like us. The discoveries about their genetic makeup described in the article below imply they may be more than just infectants. It suggests that possibly there's something like a symbiotic relationship going on.

"Giant Viruses Carry Genetic Code That May Control The Metabolism of Living Things" | ScienceAlert

The more we discover about giant viruses, the more questions we seem to have. Unlike most viruses, these giant strains are so large they can even be mistaken for bacteria, and the size and complexity of their genomes seem to present no end of mysteries.

Giant viruses were only first identified this century, but numerous such finds since then have challenged our long-held assumptions about what viruses really are, including whether they should in fact be considered living creatures after all.

Some of these giant viruses even seem to create their own genes; others possess genetic code we've never encountered anywhere before.

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In addition to finding expected genes for processes such as capsid construction and viral infectivity, the team found giant viruses harbour a huge diversity of genes involved in aspects of cellular metabolism, including processes such as nutrient uptake, light harvesting, and nitrogen metabolism.

Metabolic genes have been identified in viruses before, but this is something different, the researchers say.

Previous research in NCLDVs [nucleocytoplasmic large DNA viruses] has uncovered genes thought to be acquired from cellular life through lateral gene transfer - the movement of genetic material between organisms, as opposed to it being passed down from parent to offspring. In the viral context, this suggests viruses might acquire genes by chance from infected hosts.

Here, however, the team found evolutionary lineages of viral metabolic genes that went far deeper, suggesting longstanding relationships between pathogens and hosts, the symbiotic significance of which we can't yet fully unravel.

"It implies that the viruses have had these genes for millions of years, even billions of years, and they're virus-specific metabolic genes," Aylward explains.

"Once viruses infect a cell, we can't think of the cell as being its own autonomous entity anymore. The fundamental aspects of cellular physiology are being rewired by these viruses upon infection."

In other words, giant viruses and their ancient ancestors may have dwelled alongside cellular organisms for eons, not only replicating inside the cells of living creatures, but exerting an unseen influence on their metabolic processes all this time.

[Continues . . .]

[xSilverPhinx]

That's really cool.