You *can* teach an old dog new tricks

One biologist even suggested that the cells should be consider a new species.

That's... amazing.

I can't help but wonder, though (assuming they're right that this is a pathenogenic cancer line and not just a pathogenic virus with a symptomatic cancer):

So, gee, when random mutation changed the dog genome to enable these cancerous dog cells to survive as an independent parasite that can propagate and survive in hosts other than the one they originated in... was this an "increase" or a "decrease" in "information"?

I've been using HeLa cells as an example of possible cross-phylum macroevolution for a while now. Good to know I have even more ammo on the same level!

Importantly, this speciation event must have involved a series of highly specialized adaptations, e.g. to maximize "seeding", grafting to different tissues, immune evasion (unlike conventional cancer cells, these guys are able to avoid immune responses in genetically very different hosts). "Just a loss of information" this ain't.

unlike conventional cancer cells, these guys are able to avoid immune responses in genetically very different hosts

Can you elaborate on this? Did somebody go to the bother of testing implanting tumors in foreign hosts at some point or something?

Uh, I guess I'm dumb, but I couldn't see what makes this different from a cancer-causing virus. Is it just because of the difference in the genetic markers? This makes it a new species? I guess someone will shell out for the full genome analysis then, since it would be such a huge evolutionary discovery?

Recall that bacterial flagella help bacteria hold on to human cells and cause diarrhea, which is still a leading cause of infant death in the third world.

Now the full truth is out: the Designer hates kids and dogs.

Never mind, I see. The genetic markers tell them that the cancer cells are not from the host dog, but are the immortal cells of a long dead dog. Got it.

Now the full truth is out: the Designer hates kids and dogs.

If I thought that "phylum" and "phylum-level bodyplan" were inviolable, unchanging character complexes (which I don't), this example of a super-phyletic macroevolutionary change, on microevolutionary timescales, would rock my world.

It's not a dog anymore, is it?

... I couldn't see what makes this different from a cancer-causing virus. Is it just because of the difference in the genetic markers?

This makes it a new species?

I think the difference is, unless I've read it wrong, that there is no virus.

But skeptics noted that virus-like particles are often found in or around Sticker's sarcoma. There's lots of strong evidence that viruses can trigger cancers (such as cervical cancer), possibly as a strategy to spread themselves rapidly. Dogs that were struck with Sticker's sarcoma could just be acquiring a cancer-causing virus from other dogs.

Yeah, the adult Sacculina has ditched the arthropod body plan and changed into very bizarre parasite.

Now consider Devil Facial Tumor Syndrome. A contagious cancer found in tasmanian devils, thought to be picked up from dogs. DFTS is found on the face, and in most cases eventually grows to interfere with breathing. This resulting in the animal's suffocation.

The tumor cells have been found to have devil DNA, but not that of the victim per se. In addition, anomalous DNA has been found in those same cells not otherwise found in tasmanian devils.

Since DFTS is apparently descended from Sticker's Sarcoma it could be we have the first speciation event in a new phylum.

Yeah, the adult Sacculina has ditched the arthropod body plan and changed into very bizarre parasite.

Oops, I see that the Wikipedia article links to Zimmer's. Nevermind.

I think the difference is, unless I've read it wrong, that there is no virus.

But skeptics noted that virus-like particles are often found in or around Sticker's sarcoma. There's lots of strong evidence that viruses can trigger cancers (such as cervical cancer), possibly as a strategy to spread themselves rapidly. Dogs that were struck with Sticker's sarcoma could just be acquiring a cancer-causing virus from other dogs.

They noted that the tumor cells appeared to share a unique genetic marker.

My god. I never thought we'd have a more perfect example of macroevolution than HeLa. This is stunning.

And I don't even have to feel all that bad for the dogs!

Are we supposed to read "virus-like particles" as a virus, or just an alternate possiblity?

Dogs that were struck with Sticker's sarcoma could just be acquiring a cancer-causing virus from other dogs.

Could a virus be injecting the unique marker?

P.S. Norm, if it seems like I'm quibbling, you're probably right; we don't have any substantive disagreement. But instead of saying that the difference is that there is no virus, I would have said that the difference is that the tumors reproduce, rather than each independently being caused by a virus. For all we know, the tumors are hosts to some virus, which might explain the virus-like particles, in which case there is a virus, but it's not relevant.

Do HeLa cells have a "right to life"?

Is it humane to continue to perform experiments on human organisms?

The issues under discussions:

1. The possible contribution of a virus to the origin to the tumor versus the LINE insertion upstream of c-myc.
2. The origin and development of the unique genetic and cell surface markers.
3. The tumor/host immune system interactions.

These issues differentiate this discussion and its approach to the study of this unique cell by raising specific testable hypotheses. This is in contrast to ID claims of testability where they continue to generate negative or untestable hand waving arguments.

Delta Pi Gamma (Scientia et Fermentum)

Proposition: The virus-like particles are expressions of the cancer cells themselves. The coding therefor inserted into the cell by the original virus. Thus what we have is not a virus per se, but a reminder of the virus.

Update. The Wikipedia article on Devil Facial Tumor Disease (DFTD) can be found here. It has links to other articles on the condition.

Note that DFTD has been connected to Stickers Sarcoma

Proposition: The virus-like particles are expressions of the cancer cells themselves. The coding therefor inserted into the cell by the original virus. Thus what we have is not a virus per se, but a reminder of the virus.

The coding therefor inserted into the cell by the original virus

All of the tumor cells shared the same genetic marker. A virus-like stretch of DNA, called a LINE-1 element, had been moved to a new location in the genome of all of the tumor cells. None of the non-tumor cells from the dogs had this LINE-1 element in this particular spot.

The scientists propose that several centuries ago, a histiocyte cell in a dog or a wolf turned cancerous. A mutation may have caused the cell to become abnormal--perhaps that LINE-1 element that marks Sticker's sarcoma cells today.

OK, just to clarify some points:
- there are many different types of viruses (with both DNA and RNA genomes) that are known to be involved in the transformation of normal cells into tumor cells;
- It is entirely possible that the original tumor causing CTVT may have been caused by such a virus, and that the CTVT cells still harbor the virus, and maybe even shed viral particles;
- There is however little if any conclusive molecular evidence of viral infection of CTVT cells;
- Regardless, as pointed out by Popper's Ghost and others above, the evidence in the Cell paper convincingly shows that the causative, transmissible agent of CTVT today is the cell line itself, not any associated virus.

Nice summary, Andrea. I didn't actually say that the evidence is convincing, just strongly suggestive, because I'm cautious about being convinced of anything, I haven't read the paper or anything else relevant other than Zimmer's post, and I'm not qualified or competent to make conclusive judgments about such things.

interesting!