
New Species May Evolve from Cancers - jessaustin
https://www.quantamagazine.org/can-new-species-evolve-from-cancers-maybe-heres-how-20190819/
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vharuck
For the biologists out there: what parts of this theory are limited by actual
phenomena? What parts just push the bounds of a mental model used by
scientists to help understand biology? As a non-biologist, it's sometimes hard
to know the difference.

Also, what are the arguments for not saying transmissible cancers are
parasites?

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dfsegoat
It's helpful to see how there are fundamental precedents for externally
mediated genomic change, which may then give rise to phenotypic ("what we
see") or genomic ("the source code of what we see") differences:

Transposons or "jumping genes" [1] are segments of DNA code which can move
around within a genome by themselves (autonomously).

Presumably though, over time, enough of these moving in the right place - in
combination with some other mutation - might confer some benefit that leads to
speciation [2].

edit: length / clarity

[1] -
[https://en.wikipedia.org/wiki/Transposable_element](https://en.wikipedia.org/wiki/Transposable_element)

[2] - [https://www.scientificamerican.com/article/wandering-fly-
gen...](https://www.scientificamerican.com/article/wandering-fly-gene-suppor/)

~~~
aluren
DNA is nothing like source code. Why do people keep repeating this analogy.

At any rate, cell differentiation/compartmentation _within_ a tumor has been
observed, so things do get blurry indeed. It's also worth noting that there
isn't a single definition of 'species' and it's all just semantics that
changes depending on your field. (The traditional 'inter-fertile over two
generations' you learn in high school is helpful but doesn't stand up to many
observations.) Ultimately a species is what biologists say is a species.

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NoGravitas
I'm not sure what triggered the association for me, but it reminded me of
Peter Watts' _The Things_.

[http://clarkesworldmagazine.com/watts_01_10/](http://clarkesworldmagazine.com/watts_01_10/)

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knolax
I remember in that short story The Thing begins to call _humans_ "living
cancer" because of how specialized human cells were to the point that cells in
certain structures like the brain wouldn't be able to support themselves on
their own.

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fiblye
Strange question, but at some point, could the self-sustaining cancer cells
taken from Henrietta Lacks be considered a separate species?

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selimthegrim
I think they need a special environment?

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fiblye
Technically, all life does.

According to Wikipedia, the cells have a tendency to contaminate pretty much
any suitable environment around and proliferate easily. Seems almost more like
a fungal or bacterial growth than what we’d typically consider cancer.

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lawlessone
Does it still contain all the information that makes Henrietta Henrietta? like
face structure, hair colour etc?

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Santosh83
Probably, but may have significantly mutated all over the place, corrupting
that information. Additionally there are more stable chromosomes than in a
normal human.
[https://en.wikipedia.org/wiki/HeLa#Chromosome_number](https://en.wikipedia.org/wiki/HeLa#Chromosome_number)

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vanderZwan
> _Some species also have complex features, such as cells organized into
> structures resembling muscles for movement, for example. She just doesn’t
> find it plausible that such complexity arose from a cancer._

Wouldn't that (theoretically) be be easier for cancer cells? The article
doesn't state if these muscles came from "new" genes that were evolved for
this or if they reactivated pre-existing genes from more complex ancestors,
but the latter seems like a significantly smaller evolutionary leap than the
former, and cancer cells would be in the unique position to be able to do
that.

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pvaldes
I had seen a lot of Myxozoa previously. I remember being thrilled when the
origin of Myxosporeans were disclosed. It was a "in your face" moment. The
cnidarian traits were clearly there for anybody to see it.

But I agree that many have just too complex life cycles to be a cancer. The
idea of a microbe using a TASER like weapon is also really bizarre if we think
about it. They are also too numerous to appear just by chance (again and
again), and then evolve to attack seaworms, and later evolve again to invade
fishe's hearts, muscles, gallbladders, gills... too much stable complexity for
a cancer.

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vikramkr
I know a few people that would argue that HeLa cells night as well be their
own separate species after dealing with cell line contamination and all by
HeLa cells, it's more in a joking sense afaik but there might be something to
treating some of these cancer cell lineages as new species

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geocrasher
I seem to remember there being an X-Files episode that presented this theory.

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hsnewman
So they may not as well? Is this news?

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tabtab
Explains why that red lump on my back asked to borrow some cash.

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aszantu
Reminds me of Tasmanian devil with the transmissible face cancer

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logfromblammo
[https://en.wikipedia.org/wiki/Devil_facial_tumor_disease](https://en.wikipedia.org/wiki/Devil_facial_tumor_disease)

Or CTVT

[https://en.wikipedia.org/wiki/Canine_transmissible_venereal_...](https://en.wikipedia.org/wiki/Canine_transmissible_venereal_tumor)

Parasitic transmissible cancers are very rare, because they generally lack the
ability to adapt genetically, and get wiped out after a few thousand years,
when all their accumulated mutations start to impact their survivability.

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geggam
Isnt this a movie ?

