Immediately, Long ago we created from mitochondria She has her own genes: Although it cannot live outside a cell, this indicates that it was originally a separate organism. But more recently, the genetic sequence of today’s bacteria is thought to be the closest relative of the first bacteria eukaryotes The first, more complex organisms revealed genes that appeared to come neither from the “host” nor from the “intruder”.
This is not just a discussion obsessed from genetics. The arrival of mitochondria in biology is a key moment in evolution, allowing the passage from bacteria without a nucleus – prokaryotes – to more complex organisms – eukaryotes – including plants and animals.
The Scientific American to remember That in 2021, evolutionary geneticist Tony Gabaldon published His team’s results deciphering a wide range of eukaryotes, and finding genes in them that emerged for themselves come from a wide range of ancestors other than those putatively from mitochondria or primitive bacteria. One of their hypotheses is that, over time, there may have been more than one attempt at coexistence, of which only our “attempts” could have succeeded. Another hypothesis is that many bacteria may be absorbed over time, leaving some of their genes behind. In any case, “it is now clear that there were additional contributions from both partners.” And this is without taking into account the fact that some of the internal structures of our cells can also have an “external” origin, such as the membranes of “modules” or organelles.
Biology has a name for it: inner coexistence, that is, when an organism lives inside another organism. In many cases, they depend on each other. The fact that the most recent endosymbiosis has been observed—barely 100 million years or less—can also make it possible to better measure how long it takes to establish such a ‘link’ and ‘select’ which genes and which proteins will be indispensable.
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