More than half your body is not human

[Prometheus]

19 minutes ago, StringJunky said:

Like gamblers only brag about their winnings.

Yep. Except you could divide sci-fi authors into two camps: those who actually try to extrapolate the future based on current scientific progress and those who just want to tell a story within the context of some future, fanciful or otherwise.

But in an attempt to keep this on-topic i'd be interested to know about any sci-fi stories which utilise the microbiome. Maybe plants influencing humans by introducing some organisms into the human gut flora.

[StringJunky]

1 minute ago, Prometheus said:

Yep. Except you could divide sci-fi authors into two camps: those who actually try to extrapolate the future based on current scientific progress and those who just want to tell a story within the context of some future, fanciful or otherwise.

But in an attempt to keep this on-topic i'd be interested to know about any sci-fi stories which utilise the microbiome. Maybe plants influencing humans by introducing some organisms into the human gut flora.

That would be interesting.

[Prometheus]

This paper explores some of the mood-changing organisms, might be a good place to start. 

[StringJunky]

5 minutes ago, Prometheus said:

This paper explores some of the mood-changing organisms, might be a good place to start. 

Cool. This link is not behind a paywall:

https://pdfs.semanticscholar.org/7674/a8c3fd0032492ff794643df1b55627ddd9b1.pdf

[Sensei]

20 minutes ago, Prometheus said:

This paper explores some of the mood-changing organisms, might be a good place to start. 

That reminds me "zombie-ant fungus" ("Ophiocordyceps unilateralis")

https://en.wikipedia.org/wiki/Ophiocordyceps_unilateralis

(read Life Cycle at least)

 

[MarkE]

On 4/10/2018 at 11:41 AM, StringJunky said:

Human cells make up only 43% of the body's total cell count. The rest are microscopic colonists.

The field is even asking questions of what it means to be "human" and is leading to new innovative treatments as a result.

Interesting topic! I was discussing the same subject with CharonY earlier (in this topic). If this hypothesis is correct, then this would mean that the remaining 57%, the "human" part, is not human at all, since the eukaryotic cell itself is made up from bacteria, archaea and yes, even viruses (our cell nucleus):

On 4/5/2018 at 12:28 PM, MarkE said:

@CharonY, do you support the eukaryogenesis hypothesis, which states that the eukaryotic cell nucleus is derived from a virus?

According to the viral eukaryogenesis hypothesis, the eukaryotic cell is a composite of three phylogenetically unrelated organisms: a viral lysogen that evolved into the nucleus, an archaeal cell that evolved into the eukaryotic cytoplasm, and an alpha-proteobacterium that evolved into the mitochondria.

A lysogenic helical virus with a bilipid envelope (such as the pox virus) bears a distinct resemblance to a highly simplified cellular nucleus (i.e., a DNA chromosome encapsulated within a lipid membrane.

What are your thoughts about this hypothesis?

 

Edited April 12, 2018 by MarkE

[StringJunky]

7 minutes ago, MarkE said:

Interesting topic! I was discussing the same subject with CharonY earlier (in this topic). If this hypothesis is true, that would mean that the remaining 57%, the "human" part, is not human at all, since the eukaryotic cell itself is made up from bacteria, archaea and yes, even viruses (our cell nucleus):

 

Yes,it is interesting, but as CharonY says:

Quote

This is not really an integration into human (or eukaryotic) functions. Archaea and bacteria are the precursor of the eukaryotic cell. I.e. you are talking about evolutionary history. 

I am still working on a riposte.  

Edited April 12, 2018 by StringJunky

[CharonY]

Also, I'd like to re-iterate that most evidence point to a prokaryotic origin of the nucleus.

[MarkE]

52 minutes ago, CharonY said:

Also, I'd like to re-iterate that most evidence point to a prokaryotic origin of the nucleus.

Do you support the RNA world hypothesis? If so, isn't it more probable to suggest a viral ancestor first, and a bacterial/archaeal ancestor that came after, because only viruses can have RNA-based genomes, whereas all other life forms have DNA-based genomes?

One of the problems with the RNA world hypothesis is to discover the pathway by which RNA became upgraded to the DNA system. While conducting a survey of viruses in a hot acidic lake, scientists uncovered evidence that a simple DNA virus had acquired a gene from a completely unrelated RNA-based virus. It is suggested that viruses are capable of converting an RNA-based gene into DNA and then incorporating it into a more complex DNA-based genome, some 4 billion years ago. This finding supports the argument for the transfer of information from the RNA world to the emerging DNA world before the emergence of the last common ancestor. From the research, the diversity of this virus world is still with us.

Edited April 12, 2018 by MarkE

[CharonY]

I think we discussed that already. Even if you assume that RNA was an early system there is no direct evidence that viruses evolved at that point. The missing link is the lack of viruses to produce protein themselves to facilitate the variety of functions it would require to reproduce. The two possible scenarios is that there was a system, but it vanished (and it would be difficult to trace them for these reasons) or they developed at least after proto-cell functions were established. Most evidence point to the latter. I think the issue is that you implicitly assume that RNA proto-cells  are automatically viruses, which is a misunderstanding of the current discussion regarding the emergence of life. The paper that you linked also describes that the chimeric structure would be  consequence of an ancestral host able to accommodate both  types of viruses.

One emerging view that original cell types were RNA-cells and the transition to DNA cells was fueled by parasitism by RNA viruses. I.e. viruses arose early, before LUCA. But again, it would be a concurrent development to cellular lineages which eventually lead to today's prokaryotes. Thus viruses could be considered shapers of proto-cells leading to the modern cell but not actual precursors,  

[MarkE]

1 hour ago, CharonY said:

I think we discussed that already. Even if you assume that RNA was an early system there is no direct evidence that viruses evolved at that point. The missing link is the lack of viruses to produce protein themselves to facilitate the variety of functions it would require to reproduce. The two possible scenarios is that there was a system, but it vanished (and it would be difficult to trace them for these reasons) or they developed at least after proto-cell functions were established. Most evidence point to the latter. I think the issue is that you implicitly assume that RNA proto-cells  are automatically viruses, which is a misunderstanding of the current discussion regarding the emergence of life. The paper that you linked also describes that the chimeric structure would be  consequence of an ancestral host able to accommodate both  types of viruses.

One emerging view that original cell types were RNA-cells and the transition to DNA cells was fueled by parasitism by RNA viruses. I.e. viruses arose early, before LUCA. But again, it would be a concurrent development to cellular lineages which eventually lead to today's prokaryotes. Thus viruses could be considered shapers of proto-cells leading to the modern cell but not actual precursors,  

I really would like to understand all of this, so I hope you don’t mind me bringing earlier discussions up again.

You’re saying that the first RNA cell doesn’t necessarily have to be a virus. But what’s the other option? Earlier, you wrote “most evidence point to a prokaryotic origin of the nucleus”, but a prokaryote is already a very complex cell. Before a strand of DNA, there must have been a strand of RNA first (just like the modern virions) which, at some point, must have encapsulated itself with, or hijacked, a (self-assembling) lipid bilayer as a membrane. Isn't the least complex cell type that of a virus?

You're referring to "one emerging view”, but I have a hard time visualising the fuelling mechanism you're describing. Could you provide any references to this (new?) emerging view, because it sounds very interesting. And thanks for explaining (again), by the way.

[CharonY]

To avoid hijacking I have left a comment on the other thread.