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> Archaea lipids behave differently than those found in bacteria and eukaryotes That's a hell of a thing to drop with no further explanation. I thought eukaryo

> Archaea lipids behave differently than those found in bacteria and eukaryotes That's a hell of a thing to drop with no further explanation. I thought eukaryotes were supposed to have evolved from basically archaea, or at least very archaea-like ancestors. How do eukaryotes end up sharing chemistry with bacteria but not archaea?

kleton 2y ago
Archae have ether linkages in their lipids, bacteria and eukaryotes have glycerol esters.
Sniffnoy 2y ago
Bacterial genes migrating from the mitochondria to the nucleus -- or at least, that's the theory I read in "The Vital Question" by Nick Lane.
unddoch 2y ago
It's one of the problems with the 'current' model of Eukaryogenesis. Eugene Koonin has recently suggested an interesting two stage model based also on shared virus phylogenies: https://www.nature.com/articles/s41564-023-01378-y https://www.nature.com/articles/s41564-023-01378-y
adrian_b 2y ago
The eukaryotes share most of their metabolic paths with bacteria instead of archaea, not only their membrane composition. Because all the known eukaryotes have their origin after the symbiosis with the bacteria that have become mitochondria and most of the genome of the mitochondria has been moved to the nucleus, one possibility is that all the bacterial characteristics of the eukaryotes come from the ancestor of mitochondria. There are alternative hypotheses, e.g. that there have been a few other symbiosis events with some bacteria, before the symbiosis with the ancestor of mitochondria, so some of the bacterial characteristics are inherited from different bacteria. A possibility is that some of the differences between archaea and bacteria have arisen after the divergence between archaea and eukaryotes, so the bacterial characteristics of the eukaryotes would be primitive. However this supposition has become more unlikely during recent years, because some evidence has accumulated that appears to support a closer relationship between eukaryotes and some of the archaea than with the other archaea, in which case all characteristics shared by all archaea would predate the divergence with the eukaryotes.

kleton 2y ago

Archae have ether linkages in their lipids, bacteria and eukaryotes have glycerol esters.

Sniffnoy 2y ago

Bacterial genes migrating from the mitochondria to the nucleus -- or at least, that's the theory I read in "The Vital Question" by Nick Lane.

unddoch 2y ago

It's one of the problems with the 'current' model of Eukaryogenesis. Eugene Koonin has recently suggested an interesting two stage model based also on shared virus phylogenies: https://www.nature.com/articles/s41564-023-01378-y https://www.nature.com/articles/s41564-023-01378-y

adrian_b 2y ago

The eukaryotes share most of their metabolic paths with bacteria instead of archaea, not only their membrane composition. Because all the known eukaryotes have their origin after the symbiosis with the bacteria that have become mitochondria and most of the genome of the mitochondria has been moved to the nucleus, one possibility is that all the bacterial characteristics of the eukaryotes come from the ancestor of mitochondria. There are alternative hypotheses, e.g. that there have been a few other symbiosis events with some bacteria, before the symbiosis with the ancestor of mitochondria, so some of the bacterial characteristics are inherited from different bacteria. A possibility is that some of the differences between archaea and bacteria have arisen after the divergence between archaea and eukaryotes, so the bacterial characteristics of the eukaryotes would be primitive. However this supposition has become more unlikely during recent years, because some evidence has accumulated that appears to support a closer relationship between eukaryotes and some of the archaea than with the other archaea, in which case all characteristics shared by all archaea would predate the divergence with the eukaryotes.