RNA Evolves to an Ecosystem of Hosts & Parasites

It takes awhile though!

About a decade ago... Ichihashi and his team developed an RNA molecule that encoded a replicase, which can make copies of RNA. But for the molecule to translate its own code, the scientists needed to add something more: ribosomes and other gene translation machinery that they borrowed from the common gut bacteria Escherichia coli. They embedded the machinery inside droplets and added them to a mixture of RNAs and raw materials.

...

After 215 hours and 43 rounds of replication, the researchers began to see interesting results, ... The original RNA had been replaced by lineages of two other RNAs. One, which the researchers described as a “host,” could use its own replicase to copy itself, like the original molecules. The other lineage, a “parasite,” needed to borrow the gene expression machinery of the hosts.

Popular article:
https://www.quantamagazine.org/in-test-tubes-rna-molecules-evolve-into-a-tiny-ecosystem-20220505/

Technical report:
https://www.nature.com/articles/s41467-022-29113-x

Looks like we are starting to understand 'Life' and 'Evolution'.

Cheers,
Tom

That's really interesting, Tom. It's amazing to think that scientists were able to create something that mimics life in a test tube. It definitely took a while to develop this molecule, but the possibilities it opens up are exciting. Thanks for sharing!

I have to admit I find some of these reports difficult to make sense out of, we can't really avoid the issue of defining what we mean by life. There are clearly some proteins that are capable of interacting with the environment in ways that add to their own structure or change the structure of other proteins they come into contact with. While this is self replication, it's not really life, even though they may behave in ways that resemble life. An example of this might be prion proteins, which trigger changes in other similar proteins they come into contact with. These were thought to cause abnormalities and diseases but are now thought to be fairly common with some serving physiological functions in the body. However, they are incapable of independent metabolic functions and are not considered to be alive.

The same issue is present in our understanding of viruses, which have evolved alongside cells and are dependent of cells for all the functions we associate with life, a virus isn't an independent for of life, it is a virus infected cell that is a lifeform.

The article makes a number of claims about RNA spontaneously evolving and developing complexity through Darwinian evolution, a claim that makes no sense, the RNA of viruses “evolves” because of errors in its replication, which happens inside a cell. The claim that they developed five different molecular “species” or lineages of hosts and parasites that coexisted in harmony and cooperated to survive, evolved cooperation, sounds like a fantasy.

They do eventually describe the addition of the mechanisms for reproduction from a bacterium, this like many similar experiments isn't really about the creation of new forms of life, it's about constructing organisms from pre-existing parts.