Can a tumor become a new form of life?

[AK-Dave]

The title of this thread is the first line of a very interesting article on The Loom, one of the ScienceBlogs. Read it here (http://scienceblogs.com/loom/2006/08/09/an_old_dog_lives_on_inside_new.php).

Does this count as a new species (or even a new phylum)?

If so, as one of the comments on the above linked blog said:... now there's a twist to the creationist canard. "You'll never see a dog evolve into a cat!" Well, we might have just seen a dog evolve into a parasitic tumor creature.

Very cool stuff. Now why can't the ID people generate interesting contributions to science like this?

As a bonus, I'd never heard of the HeLa (http://en.wikipedia.org/wiki/HeLa) line of immortal cells, which is also really interesting science.

-David

[fuelair]

The title of this thread is the first line of a very interesting article on The Loom, one of the ScienceBlogs. Read it here (http://scienceblogs.com/loom/2006/08/09/an_old_dog_lives_on_inside_new.php).

Does this count as a new species (or even a new phylum)?

If so, as one of the comments on the above linked blog said:

Very cool stuff. Now why can't the ID people generate interesting contributions to science like this?

As a bonus, I'd never heard of the HeLa (http://en.wikipedia.org/wiki/HeLa) line of immortal cells, which is also really interesting science.

-David

The HeLa story is marvelous - indirectly she will probably outlive us all!!

[AK-Dave]

The HeLa story is marvelous - indirectly she will probably outlive us all!!So will a dog that lived 250 to 2500 years ago, based on the article. In the wikipedia link, it states: "It has been estimated that the total mass of HeLa cells today far exceeds that of the rest of Henrietta Lacks' body." I'm assuming they meant her mass when she was still alive. I can't decide if that is cool or creepy.

-David

[skeptigirl]

Canine transmissible venereal tumour (CTVT) (http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed&cmd=Retrieve&dopt=AbstractPlus&list_uids=14535580&query_hl=4&itool=pubmed_docsum) is the only known naturally occurring tumour that can be transplanted as an allograft across major histocompatibility (MHC) barriers within the same species, and even to other members of the canine family, such as foxes, coyotes and wolves....this is followed by transplantation immunity in immunocompetent adults, while metastasis occurs in puppies and immunosuppressed dogs....

Normally tumors are the hosts own cells gone awry.

Typically foreign tissue is attacked as an invader. The body's immune system attacks invading cells inefficiently until the antigen (the invader) - antiboby (the immune complex) response develops specificity. Then the immune response is more efficient with the exception of organisms that develop means of defeating the immune system.

Tumors can be triggered by various assaults on the cell's DNA including viruses. Viruses contain their own genetic material (RNA or DNA) which inserts itself into the cell and either causes viral replication in the cytoplasm or enters the nucleus and initiates viral replication there. In the nucleus, cell replication instead of, or in addition to viral replication can occur. A number of viruses are known carcinogens like the hepatitis B virus which is one of the leading causes of cancer in the world.

Then we have prions which are not even genetic material but which are transmissable proteins which cause a chain reaction of abnormal protein folding in the brain to cause the spongiform encephalopathies like Mad Cow Disease.

I bring this information up to get to the question, what is a life form? Many are not sure whether viruses should be considered a life form let alone should prions. Others define life as being able to replicate but then where do prions end and crystals begin?

There are many bacteria which survive within other living cells such as gonococcal bacteria which are obligate intracellular organisms meaning they are found inside other cells. So needing a host cell doesn't define non-life as no one would argue gonococcal bacteria were not a life form.

Cell lines as noted with the HeLa cell lines are frequently maintained in laboratory settings without requiring the whole organism they originated from. But would we define liver cells as a species because they are maintained and grown in a petri dish?

With that I leave the pondering since there is no good answer here. One does have to wonder whether these transmissible tumors originated from a single canine or whether they arose spontaneously more than once. If anyone finds that out let us know because I am curious.

[born]

Normally tumors are the hosts own cells gone awry.

Typically foreign tissue is attacked as an invader. The body's immune system attacks invading cells inefficiently until the antigen (the invader) - antiboby (the immune complex) response develops specificity. Then the immune response is more efficient with the exception of organisms that develop means of defeating the immune system.

Tumors can be triggered by various assaults on the cell's DNA including viruses. Viruses contain their own genetic material (RNA or DNA) which inserts itself into the cell and either causes viral replication in the cytoplasm or enters the nucleus and initiates viral replication there. In the nucleus, cell replication instead of, or in addition to viral replication can occur. A number of viruses are known carcinogens like the hepatitis B virus which is one of the leading causes of cancer in the world.

Then we have prions which are not even genetic material but which are transmissable proteins which cause a chain reaction of abnormal protein folding in the brain to cause the spongiform encephalopathies like Mad Cow Disease.

I bring this information up to get to the question, what is a life form? Many are not sure whether viruses should be considered a life form let alone should prions. Others define life as being able to replicate but then where do prions end and crystals begin?

There are many bacteria which survive within other living cells such as gonococcal bacteria which are obligate intracellular organisms meaning they are found inside other cells. So needing a host cell doesn't define non-life as no one would argue gonococcal bacteria were not a life form.

Cell lines as noted with the HeLa cell lines are frequently maintained in laboratory settings without requiring the whole organism they originated from. But would we define liver cells as a species because they are maintained and grown in a petri dish?

With that I leave the pondering since there is no good answer here. One does have to wonder whether these transmissible tumors originated from a single canine or whether they arose spontaneously more than once. If anyone finds that out let us know because I am curious.
Just a thought to get this thread moving. Could something such as a fungal mass constitute or be losely termed a transmissable tumor?

[Eos of the Eons]

Not usually (I think you are thinking of the Morgellons here).

Fungi will have a variety of ways of reproducing, but since they don't invade host cells with their own dna, then they don't really cause tumours. Fungi are parasites that break down and ingest their host, rather than invading the way viruses do.

[born]

Not usually (I think you are thinking of the Morgellons here).

Fungi will have a variety of ways of reproducing, but since they don't invade host cells with their own dna, then they don't really cause tumours. Fungi are parasites that break down and ingest their host, rather than invading the way viruses do.
Back to school with you! If I am not misunderstanding you, you are saying that fungus cannot invade a cell?
Fungi can indeed become intracellular.

[Soapy Sam]

Indeed there are toadstools in many cellars.

[Eos of the Eons]

Back to school with you! If I am not misunderstanding you, you are saying that fungus cannot invade a cell?
Fungi can indeed become intracellular.
:D I meant they cannot insert themselves into our dna and make our cells grow stuff it wasn't meant to.

[skeptigirl]

:D I meant they cannot insert themselves into our dna and make our cells grow stuff it wasn't meant to.Life comes in an amazing variety. (http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=8825473&dopt=Abstract) It's always wise to check these things before commenting if it isn't one's area of expertise. And even then....

[skeptigirl]

Just a thought to get this thread moving. Could something such as a fungal mass constitute or be losely termed a transmissable tumor?
Some fungi certainly produce tumors and tumor like growths but I believe they do not meet the definition of a transmissable tumor.

One thing that makes a tumor a tumor is the cells are from the lifeform or at least another one of the group. Fungi would be a different life form living in/on or from the material of a second lifeform.

A parasite might be a better definition. But then I am not a mycology expert and don't really know. Considering how complex defining these things can get, I think I'll leave it at that.

[Eos of the Eons]

Life comes in an amazing variety. (http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=8825473&dopt=Abstract) It's always wise to check these things before commenting if it isn't one's area of expertise. And even then....

That's okay, I don't being proven wrong with something that is right and the chance to increase my own knowledge.

What I can understand is that they have their own genes that code for something, but does it actually get the fungi dna into the plant dna?
Signaling between pathogen and plant is of key importance in tumor induction and fungal growth and differentiation within the plant.
Or is the fungi just able to get a good growth that mimics the plant a bit to allow it to reproduce?


I believe they do not meet the definition of a transmissable tumor

Good enough to answer the question. Thanks!

[SteveGrenard]

There is a contagious type of cancer in dogs which act like parasites.



Contagious cancer cells act like parasites, infecting dogs around the world, say scientists studying the oldest known cancer cells.

Canine transmissible venereal tumour, or CTVT, apparently spreads between domestic dogs through sexual contact and may also spread through licking, biting or sniffing affected areas.

Unlike cervical cancer in humans, which is caused by a virus, the dog cancer spreads by the tumour cells themselves rather than a virus.

http://www.cbc.ca/story/science/national/2006/08/10/cancer-dogs.html

[AK-Dave]

There is a contagious type of cancer in dogs which act like parasites.

Which is the specific cancer the article in the first post discusses. Does it count as a new species since the cancer cells are decendants of a tumor from a dog that lived 250-2500 years ago? Most cancers are the organisms own cells that are growing out of control. This is different from cancers like cervical cancer, which is caused by a contagious virus. This is spread by the cancer cells themselves colonizing a new host. And all the instances of this specific cancer seem to have decended from the cancer cells of one dog.

[skeptigirl]

...

What I can understand is that they have their own genes that code for something, but does it actually get the fungi dna into the plant dna?
...Apparently the genetic material of the fungus does indeed enter the corn plant cell and control tumor formation directly. While the DNA may not fuse with the plant DNA (don't know, didn't get that far in reading about it), neither does all viral DNA fuse with cell nuclei DNA. Spores of the fungus are eventially released from the plant cells just as viruses bud from the cells they inhabit.

[skeptigirl]

There is a contagious type of cancer in dogs which act like parasites.
Skipped the OP, did you?

[Eos of the Eons]

Apparently the genetic material of the fungus does indeed enter the corn plant cell and control tumor formation directly. While the DNA may not fuse with the plant DNA (don't know, didn't get that far in reading about it), neither does all viral DNA fuse with cell nuclei DNA. Spores of the fungus are eventially released from the plant cells just as viruses bud from the cells they inhabit.


Thank you! So the fungi does cause the cell to start producing what the fungi wants it to produce. Zoinks! I learned something new today. Nasty stuff, these parasites.

Thing is, this is a plant they do this to. Is there any fungus that can do this to an animal?

[Soapy Sam]

Does this count as a new species (or even a new phylum)?
Does it matter? It's a replicator. Taxonomy is a tool for human convenience, not a straightjacket we need wear.


Very cool stuff. Now why can't the ID people generate interesting contributions to science like this?
-David
Because they are not doing science. But you knew that.

[skeptigirl]

Thank you! So the fungi does cause the cell to start producing what the fungi wants it to produce. Zoinks! I learned something new today. Nasty stuff, these parasites.

Thing is, this is a plant they do this to. Is there any fungus that can do this to an animal?Apparently so. Equine cutaneous fungal granuloma (http://www.blackwell-synergy.com/doi/abs/10.1111/j.1365-3164.2006.00525.x)

The world is getting creepier all the time. :eek:

[skeptigirl]

Does it matter? It's a replicator. Taxonomy is a tool for human convenience, not a straightjacket we need wear.
If they can work for years to come up with a definition of a planet, we can contemplate what is life and what isn't.

Besides, this may be a very important question someday depending on what kind of "replication" we find outside of the Earth's biosystems.

[Eos of the Eons]

Apparently so. Equine cutaneous fungal granuloma (http://www.blackwell-synergy.com/doi/abs/10.1111/j.1365-3164.2006.00525.x)

The world is getting creepier all the time. :eek:


I'll say! I'll be treating those fungi with more fear induced respect from now on :eye-poppi

Bloddy parasites.

Well, I don't see them producing the weird filaments people claim they get with Morgellons though. They are ugly tumours instead. I won't write off fungus so completely now though.

[Soapy Sam]

If they can work for years to come up with a definition of a planet, we can contemplate what is life and what isn't.

Besides, this may be a very important question someday depending on what kind of "replication" we find outside of the Earth's biosystems.

AK-Dave's question in the OP was about species and phylla. I don't think anyone is in doubt that this is alive. I happen to feel we have wasted far too much time and far too many words on the matter of "origin of species", "preservation of species" and the whole idea of "speciation".*

A replicator is a replicator. Whether or not it's alive is a matter of definition only and of marginal interest. Who cares if a virus is alive? If it can be crystallised , is it living then? The question of interest is- what can it do ?

Most of the human genome may originate in other species, genera, even phylla ,by the direct route rather than by what we might think of as the "normal" evolutionary route. If all eukaryotes are combinations of bacteria anyway, who cares? Life is more complicated than Darwin thought and its history even more wonderful. What fun!

ETA I typed "genera" instead of "phylla"
* Historically. Not in this thread.

[skeptigirl]

I was under the impression, Soapy, the question about whether it was a new species was intended to mean, can it be called a separate life form or is it merely tissue from a known life form.

[skeptigirl]

I'll say! I'll be treating those fungi with more fear induced respect from now on :eye-poppi

Bloddy parasites.

Well, I don't see them producing the weird filaments people claim they get with Morgellons though. They are ugly tumours instead. I won't write off fungus so completely now though.Not to change the subject but I'm of the opinion Morgellon's is a mental disorder until more evidence surfaces establishing an actual cause and not just a scratch generated rash exists. If nothing can be found in a skin biopsy, that makes it hard to buy into the parasite hypothesis. Also, in biopsies, one can determine many things about the nature of a rash.

So while the discovery of a virus or other etiology will change my mind, I think there is a point where you can say a disorder is indeed psychogenic. There have been many exceptions in the past but only rare exceptions with our current diagnostic capabilities.

[Soapy Sam]

I was under the impression, Soapy, the question about whether it was a new species was intended to mean, can it be called a separate life form or is it merely tissue from a known life form.

I get you.
I presumed he was alluding to the whole conceptual difficulty IDiots have with speciation.

We know bits of DNA have forced their way into the germline DNA of other creatures at many points in the past. (HERVs and the like, some "junk DNA".) This is a bit different from most junk DNA, in that it is actively expressed in proteins. Will it eventually be suppressed entirely by the dogs' immune systems and become non-coding junk? We don't know. It might. The replicator would then continue to survive and multiply at no cost at all to itself or at a significant cost to it's host. About 60% of the human genome seems to fit that description, implying events like this are very common indeed.
Is it a new life form? Seems like an opinion call. It's not a dog, but it reproduces using a dog. I think there is a whole range of germ line parasitic replicators we are only becoming aware of, with an equivalent range of DNA adaptations in the host genome which shut them down (but may have other effects too).