Anything New with Theobald's Work?

[Resha Caner]

Just curious. Now that it's been a few years, I wondered if anyone has tried to build upon / correct Theobald's look at common descent:

http://www.nature.com/nature/journal/v465/n7295/full/nature09014.html

 

[Loudmouth]

These may not be exactly what you are looking for, but in the same ballpark.

Molecular phylogenetics and the origin of eukaryotes/archae:
http://www.nature.com/nature/journal/v504/n7479/abs/nature12779.html

Another paper on the same subject:
http://www.hindawi.com/journals/archaea/2013/372396/abs/

If you search for "molecular phylogenetics universal common descent" at Google Scholar and choose a time frame of 2010 to present you will get a ton of papers that might interest you. Interestingly, the Theobald paper is the top result when I do that search.

 

[Resha Caner]

Thanks.

Molecular phylogenetics and the origin of eukaryotes/archae:
http://www.nature.com/nature/journal/v504/n7479/abs/nature12779.html

I'd not heard the term "three domains tree." Was that a theory of 3 separate abiogenesis origins for the 3 domains? The abstract seems to be proposing it needs to be collapsed to 2, but I was never aware of a significant argument that the origins were separate, so maybe I'm misinterpreting.

Another paper on the same subject:
http://www.hindawi.com/journals/archaea/2013/372396/abs/

Same thing here. I'm not conversant enough in the field to interpret the abstract - to decide if he's arguing for two separate abiogenesis origins or if he's just arguing that their common ancestor is older (or different) than originally thought.

If you search for "molecular phylogenetics universal common descent" at Google Scholar and choose a time frame of 2010 to present you will get a ton of papers that might interest you. Interestingly, the Theobald paper is the top result when I do that search.

Interesting. So maybe Theobald's paper has entered the realm of "seminal". Would you say Theobald's work lies firmly within evolution, or is it an issue better suited to abiogenesis, or is it a transition between the two?

 

[Loudmouth]

i'd not heard the term "three domains tree." Was that a theory of 3 separate abiogenesis origins for the 3 domains?

No. It is considered the first 3 branches of the evolutionary tree, or root ball as it turns out.

The abstract seems to be proposing it needs to be collapsed to 2, but I was never aware of a significant argument that the origins were separate, so maybe I'm misinterpreting.

The proposed history is a ton of horizontal transfer between a large pool of early life which coalesced into those three domains, but HGT still went on beyond that point. From what I have read, if there is a chance for separate abiogenesis events it will probably take the form of a metabolic-heavy abiogenesis event and a genetics-heavy abiogenesis event. One of the larger debates in abiogenesis research is which came first, metabolism or genetics. Since the two could be somewhat separate, perhaps they were slightly independent events or completely separate. However, even if they started out separately they would have had to come together at some point in what would be considered LUCA or a predecessor to LUCA.

Interesting. So maybe Theobald's paper has entered the realm of "seminal". Would you say Theobald's work lies firmly within evolution, or is it an issue better suited to abiogenesis, or is it a transition between the two?

Theobald's work lies within the framework of beating a dead horse, in many ways. He just found a new and fun way of beating the same dead horse. The work evidencing UCA is large and just short of absolute proof. Theobald's paper is a pebble on top of Mt. Everest.

 

[Resha Caner]

No. It is considered the first 3 branches of the evolutionary tree, or root ball as it turns out.

That's an interesting picture. What's the source? It gives the impression of a clever artistic means for indicating an open question: there could have been one event or multiple events.

The proposed history is a ton of horizontal transfer between a large pool of early life which coalesced into those three domains, but HGT still went on beyond that point.

OK. So, as I indicated above, that seems to leave multiple/single events as an open question ... or even the possibility that a single event produced a variety. With that would I be correct to say it indicates the predominate view is leaning toward a variety of primitive cells coming from abiogenesis?

If I am correct, how long has that been the predominate view?

From what I have read, if there is a chance for separate abiogenesis events it will probably take the form of a metabolic-heavy abiogenesis event and a genetics-heavy abiogenesis event. One of the larger debates in abiogenesis research is which came first, metabolism or genetics. Since the two could be somewhat separate, perhaps they were slightly independent events or completely separate. However, even if they started out separately they would have had to come together at some point in what would be considered LUCA or a predecessor to LUCA.

I'm not sure I get that. The "genetics-heavy" event would still have to get energy from somewhere. So does that mean it got energy from an outside source rather than metabolizing its own energy? Likewise, wouldn't the "metabolic-heavy" event need some way to propagate? What would that have been if not genetic?

I hate to impose too much, but a source on this would be very interesting if you have it close at hand.

Theobald's work lies within the framework of beating a dead horse, in many ways. He just found a new and fun way of beating the same dead horse. The work evidencing UCA is large and just short of absolute proof. Theobald's paper is a pebble on top of Mt. Everest.

If that's your position on his paper, fine. But that doesn't really answer the question. Is this squarely an issue of evolution, or abiogenesis, or some combination?

 

[Loudmouth]

OK. So, as I indicated above, that seems to leave multiple/single events as an open question ... or even the possibility that a single event produced a variety. With that would I be correct to say it indicates the predominate view is leaning toward a variety of primitive cells coming from abiogenesis?

If we are defining the first life through genetic inheritance, then there was a single origin of life as shown by universal codon usage and other features. If you loosen the definition to also include the origin of metabolic pathways, then it could get a bit murkier . . . or not. It really matters on how you view the interaction of genetics and metabolism and where the evidence will lead.

I'm not sure I get that. The "genetics-heavy" event would still have to get energy from somewhere. So does that mean it got energy from an outside source rather than metabolizing its own energy? Likewise, wouldn't the "metabolic-heavy" event need some way to propagate? What would that have been if not genetic?

Hot-cold cycles could allow things like RNA ligases to operate, or even inorganic catalysts as reaction sites. Again, this is all from my scant reading, so I could have a few details wrong.

I hate to impose too much, but a source on this would be very interesting if you have it close at hand.

I don't have a reference at hand, but a Google Scholar search for "RNA world" may find a few review articles that you would find interesting.

If that's your position on his paper, fine. But that doesn't really answer the question. Is this squarely an issue of evolution, or abiogenesis, or some combination?

Until you get competition of resources between imperfect replicators, you don't have biological evolution. You need both metabolism and genetics together in order to have the type of evolution that the modern theory describes.

Selection before that would probably be more chemical, and determined by things like solubility or rate of reaction instead of what we would call competition between organisms.

 

[Resha Caner]

I don't have a reference at hand, but a Google Scholar search for "RNA world" may find a few review articles that you would find interesting.

OK. Thanks.