5 ms·

Virus-like transposons cross the species barrier, study shows

20 points by roseway4 3y ago

roseway4 3y ago
tl;dr the presence of exactly the same gene in reproductively isolated species has puzzled scientists for some time. The example cited were two different very cold water fish which both have exactly the same “antifreeze” gene. This research group identified a type of transposon that infect worms with a virus-like ability to penetrate cells and “infect” hosts. Transposons are “greedy” particles that “transpose” DNA in order to reproduce, often at the expense of their hosts. While doing this, entire genes may be transposed. The transposon itself likely gained this ability from an encounter with a virus. Fascinating.
dboreham 3y ago
This is one of the mechanisms life uses to facilitate evolution, right? Perhaps it's even the original purpose of viruses.
- vibrio 3y ago
  Purpose of viruses? At the risk of sounding pedantic or snarky, that sounds like intelligent design. The “purpose” of viruses is to optimize making more viruses. Sloppy viral biology may allow some transfer of genes, and if that helps viruses replicate, then that activity may be codified. Please pardon, Over sensitive biologist here.
  - baerrie 3y ago
    You could make a broader claim that a “purpose” is just filling a niche in an ecological system. In this case, that niche could be enforced by advantages given to an overall ecosystem by virus/transposon gene transference. But I guess it is more of a philosophical question, can a purpose exist without an intelligence validating it? If so, you could argue everything has a purpose, if not then perhaps nothing does
    - vibrio 3y ago
      This is reasonable. A purpose sounds like a predetermined goal, which isnt how I think about viruses. They could have an effect that leads to a benefit, npbut that to me seems different than purpose. Again maybe me being pedantic, but I’ve studied on viruses and bacteria for a good amount of time so I that may lead me to think differently. I’m not intending to be judgmental.
  - ijidak 3y ago
    It doesn't sound pedantic, it sounds dogmatic. How do you definitively know that viruses have no purpose? The parent is free to make a statement about purpose.
    - vibrio 3y ago
      Just going by the definition of purpose, which I would take as the reason viruses exist. I think there could have a purpose in their “actions”, such as changing enevelope tropism to broaden target cell range, or more tightly binding a cellular protein to inhibit antiviral defenses. But to me, a non-living entity like a virus itself having a purpose for existence beyond making more virus sounds philosophical or religious— which is fine, but just not how I think about it.
  - aodonnell2536 3y ago
    Why must this “purpose” you outline be mutually exclusive with the idea of Intelligent Design?
    - vibrio 3y ago
      I don’t know. Do hydrogen atoms have a purpose? Do rocks have a purpose? I think of them having properties that maybe can be applied towards a purpose. To me Purpose implies specific intent. I’m not sure where that intent comes from for any given hydrogen atom.
      - aodonnell2536 3y ago
        I believe you’re conflating purpose with function. It seems we both agree that any attempt at assigning purpose to material objects or phenomenon is dubious at best. I think your reason for this belief is a complete rejection of the idea of Intelligent Design. As for my view, in the case that we do live in an Intelligently Designed world by some Creator, the relative gap between our respective intelligences would be too large to even comprehend. There would be no point in assigning purpose based on our observations, we can really only describe what things are and how we best understand them to function. As for intent, I agree there is no intent that can be supposed for something as one dimensional as a hydrogen atom, but perhaps intent emerges at a larger scale (e.g. life and the universe) Not trying to get too into the weeds of a religious discussion as I’m mostly agnostic, but I was surprised to see such a rejection of Intelligent Design
        vibrio 3y ago
        I wouldn’t say outfight rejection of intelligent design. If one studies viruses, much time has to be spent considering evolutionary aspects, just due to their numbers, variability, and life cycle. The involvement of an Intelligent Creator and their intents is not something I know how to test or control for. I believe there has to be a mental boundary there until that component is objectively available.
        3y ago
a_bonobo 3y ago
There are some really cool examples from marine environments with similar stories, where this jumping seems to occur more frequently (water is probably a better vector for those viruses than air) My favorite one is the family of TEs that invaded sea snake genomes independently: https://academic.oup.com/gbe/article/12/12/2370/5918459 https://academic.oup.com/gbe/article/12/12/2370/5918459 There's also cool TE jumping across hydrothermal crustaceans of different genera; https://pubmed.ncbi.nlm.nih.gov/16690328/ https://pubmed.ncbi.nlm.nih.gov/16690328/ But also be aware that horizontal gene transfer can be a false positive, sometimes you just have some contamination that looks like HGT. Most famous examples are in the human genome https://genomebiology.biomedcentral.com/articles/10.1186/s13059-017-1214-2 https://genomebiology.biomedcentral.com/articles/10.1186/s13... and in the tardigrade genome https://www.pnas.org/doi/10.1073/pnas.1600338113 https://www.pnas.org/doi/10.1073/pnas.1600338113 For some science-fiction around transposable elements, see Darwin's Radio! https://en.wikipedia.org/wiki/Darwin%27s_Radio https://en.wikipedia.org/wiki/Darwin%27s_Radio
- selimthegrim 3y ago
  Fascinating I wonder what implications this would have for the crustacean immune system
  - a_bonobo 3y ago
    There are some beautiful examples around immune systems!! Especially plants have benefited from 'domesticating' transposons to shuffle their disease resistance genes around for increased diversity -> increased chance of defense. https://genomebiology.biomedcentral.com/articles/10.1186/s13059-017-1341-9 https://genomebiology.biomedcentral.com/articles/10.1186/s13... There are some wonderful specific examples where a plant 'stole' one specific TE and uses it to generate diversity on the fly!
sacnoradhq 3y ago
DMD is caused by a mutation resulting in a transposable element. Retroviruses are TEs by definition. And, a large fraction of human DNA is ERVs, and some have become repurposed as functional proteins. Heck, some ERVs are reactivable. LINE1 is interesting in that we likely gave it to gonorrhea in some circulating strains by horizontal gene transfer within the past 20 years.

20 points by roseway4 3y ago

tl;dr the presence of exactly the same gene in reproductively isolated species has puzzled scientists for some time. The example cited were two different very cold water fish which both have exactly the same “antifreeze” gene. This research group identified a type of transposon that infect worms with a virus-like ability to penetrate cells and “infect” hosts. Transposons are “greedy” particles that “transpose” DNA in order to reproduce, often at the expense of their hosts. While doing this, entire genes may be transposed. The transposon itself likely gained this ability from an encounter with a virus. Fascinating.

dboreham 3y ago

This is one of the mechanisms life uses to facilitate evolution, right? Perhaps it's even the original purpose of viruses.

vibrio 3y ago
Purpose of viruses? At the risk of sounding pedantic or snarky, that sounds like intelligent design. The “purpose” of viruses is to optimize making more viruses. Sloppy viral biology may allow some transfer of genes, and if that helps viruses replicate, then that activity may be codified. Please pardon, Over sensitive biologist here.
- baerrie 3y ago
  You could make a broader claim that a “purpose” is just filling a niche in an ecological system. In this case, that niche could be enforced by advantages given to an overall ecosystem by virus/transposon gene transference. But I guess it is more of a philosophical question, can a purpose exist without an intelligence validating it? If so, you could argue everything has a purpose, if not then perhaps nothing does
  - vibrio 3y ago
    This is reasonable. A purpose sounds like a predetermined goal, which isnt how I think about viruses. They could have an effect that leads to a benefit, npbut that to me seems different than purpose. Again maybe me being pedantic, but I’ve studied on viruses and bacteria for a good amount of time so I that may lead me to think differently. I’m not intending to be judgmental.
- ijidak 3y ago
  It doesn't sound pedantic, it sounds dogmatic. How do you definitively know that viruses have no purpose? The parent is free to make a statement about purpose.
  - vibrio 3y ago
    Just going by the definition of purpose, which I would take as the reason viruses exist. I think there could have a purpose in their “actions”, such as changing enevelope tropism to broaden target cell range, or more tightly binding a cellular protein to inhibit antiviral defenses. But to me, a non-living entity like a virus itself having a purpose for existence beyond making more virus sounds philosophical or religious— which is fine, but just not how I think about it.
- aodonnell2536 3y ago
  Why must this “purpose” you outline be mutually exclusive with the idea of Intelligent Design?
  - vibrio 3y ago
    I don’t know. Do hydrogen atoms have a purpose? Do rocks have a purpose? I think of them having properties that maybe can be applied towards a purpose. To me Purpose implies specific intent. I’m not sure where that intent comes from for any given hydrogen atom.
    - aodonnell2536 3y ago
      I believe you’re conflating purpose with function. It seems we both agree that any attempt at assigning purpose to material objects or phenomenon is dubious at best. I think your reason for this belief is a complete rejection of the idea of Intelligent Design. As for my view, in the case that we do live in an Intelligently Designed world by some Creator, the relative gap between our respective intelligences would be too large to even comprehend. There would be no point in assigning purpose based on our observations, we can really only describe what things are and how we best understand them to function. As for intent, I agree there is no intent that can be supposed for something as one dimensional as a hydrogen atom, but perhaps intent emerges at a larger scale (e.g. life and the universe) Not trying to get too into the weeds of a religious discussion as I’m mostly agnostic, but I was surprised to see such a rejection of Intelligent Design
      - vibrio 3y ago
        I wouldn’t say outfight rejection of intelligent design. If one studies viruses, much time has to be spent considering evolutionary aspects, just due to their numbers, variability, and life cycle. The involvement of an Intelligent Creator and their intents is not something I know how to test or control for. I believe there has to be a mental boundary there until that component is objectively available.
        3y ago

a_bonobo 3y ago

There are some really cool examples from marine environments with similar stories, where this jumping seems to occur more frequently (water is probably a better vector for those viruses than air) My favorite one is the family of TEs that invaded sea snake genomes independently: https://academic.oup.com/gbe/article/12/12/2370/5918459 https://academic.oup.com/gbe/article/12/12/2370/5918459 There's also cool TE jumping across hydrothermal crustaceans of different genera; https://pubmed.ncbi.nlm.nih.gov/16690328/ https://pubmed.ncbi.nlm.nih.gov/16690328/ But also be aware that horizontal gene transfer can be a false positive, sometimes you just have some contamination that looks like HGT. Most famous examples are in the human genome https://genomebiology.biomedcentral.com/articles/10.1186/s13059-017-1214-2 https://genomebiology.biomedcentral.com/articles/10.1186/s13... and in the tardigrade genome https://www.pnas.org/doi/10.1073/pnas.1600338113 https://www.pnas.org/doi/10.1073/pnas.1600338113 For some science-fiction around transposable elements, see Darwin's Radio! https://en.wikipedia.org/wiki/Darwin%27s_Radio https://en.wikipedia.org/wiki/Darwin%27s_Radio

selimthegrim 3y ago
Fascinating I wonder what implications this would have for the crustacean immune system
- a_bonobo 3y ago
  There are some beautiful examples around immune systems!! Especially plants have benefited from 'domesticating' transposons to shuffle their disease resistance genes around for increased diversity -> increased chance of defense. https://genomebiology.biomedcentral.com/articles/10.1186/s13059-017-1341-9 https://genomebiology.biomedcentral.com/articles/10.1186/s13... There are some wonderful specific examples where a plant 'stole' one specific TE and uses it to generate diversity on the fly!

sacnoradhq 3y ago

DMD is caused by a mutation resulting in a transposable element. Retroviruses are TEs by definition. And, a large fraction of human DNA is ERVs, and some have become repurposed as functional proteins. Heck, some ERVs are reactivable. LINE1 is interesting in that we likely gave it to gonorrhea in some circulating strains by horizontal gene transfer within the past 20 years.