Major Evolution in Action

[Tom.G]

TL;DR Summary

Two lifeforms merge in once-in-a-billion years evolutionary event

"Last time this happened, the Earth got plants."

Popular version:
https://newatlas.com/biology/life-merger-evolution-symbiosis-organelle/

The deeper versions:
(open access) https://www.cell.com/cell/pdf/S0092-8674(24)00182-X.pdf
(paywall) https://www.science.org/doi/10.1126/science.adk1075
(source) https://newscenter.lbl.gov/2024/04/17/scientists-discover-first-nitrogen-fixing-organelle/

Cheers,
Tom

 

[BillTre]

This is an interesting article about the likelihood of endosymbioses (combining two different kinds of cells together to make a new evolutionary line) occurring.

These can be major events in evolution (like making eukaryotes or plants), but maybe not always.

Here is a link to a thread I made on a similar Nature article a few years ago:
https://www.physicsforums.com/threads/new-eukaryotic-endosymbiont-found.1000450/
It involves a ciliate (eukaryote, normally with mitochondria) with a degraded form of mitochondria that acquired a bacterial symbiont that could make metabolic use of nitrate to generate ATP.

How might endosymbiosis be distinguished from just a symbiosis between cells exchanging nutrients adjacent to each other in their environment?
Here are some possibilities:

• irreversible envelopment of one by the other. The internalized symbiont could be dependent on its host cell for a variety of reasons. If visualized as cell lineages (like a phylogenetic tree) the lineages of the internalized symbiont would be forever limited to being in the lineage of the host organism. Most likely the host would be dependent on the internalized symbiont in some way.
• gene transfer (usually from the internalized symbiont genome to the host genome. This would provide a clear basis for the dependance of the internalized symbiont on the host.