In his novel, Count Zero, William Gibson has his billionaire cancer patient Josef Virek say:
“Yes, Marly. And from that rather terminal perspective, I should advise you to strive to live hourly in your own flesh… I speak as one who can no longer tolerate that simple state, the cells of my body having opted for the quixotic pursuit of individual careers… I was touched, Marly, at your affairs of the heart. I envy you the ordered flesh from which they unfold.”
It turns out that the cancer cell’s pursuit of an individual career may not be as quixotic a pursuit as once thought.
Scientists studying Sticker’s Sarcoma, a cancer of dogs, recently discovered two rather surprising facts about the disease: (1) a transmittable agent causes the cancer, (2) the cells in the tumors caused by Sticker’s are definitely dog cells, (3) the cells in the tumors bear no genetic relation to each individual animal with the disease but (4) all the tumor cells in every case of Sticker’s have the same exact genes.
The only possible conclusion: Stickers Sarcoma is not a true cancer but rather a communicable pathogen that originated from one mutated cell in one dog that somehow managed to escape its original body and infect new hosts!
Wow.
A dog cell succeeded in evolving into an independent organism. Its ecological niche is the body of other dogs. Josef Virek’s quixotic quest doesn’t seem so quixotic anymore.
Commonly, we think of natural selection as concerning the change of species but modern biology views natural selection as a “force” operating on any reproducible pattern. In this view, natural selection becomes multi-level, operating like a fractal which looks the same at many different scales.
Natural selection “drives” every reproducible pattern in the body to seek to duplicate itself even at the expense of all the other patterns. Genes “try” to trigger their own duplication within the cell. Cells “try” to divide without controls.
Multicellular organism spend considerable resources controlling the reproduction of their component cells. When that control fails, cancer develops. Every one of us carries around at least one small benign knot of rogue cells that perform no function and that resulted from unregulated reproduction of some cells. One in four of us will eventually die when the controls break down in one cell completely.
The “goal” of every cancer cell is the pursuit of an individual career. The odds against any cell succeeding are obviously astronomical. Not only does the cell have to evade the host body’s attempts to regulate or destroy the rogue cell, but the cell must then find a means of jumping to and surviving in another host before it kills its initial host body. Of all the trillions of cancer cells that mutate each year in every multicellular species on earth, we know of only this one that has succeeded at some time in the last 1000 years.
I think this rare phenomenon gives a more visceral appreciation for the power of natural selection. The odds against any one dog cell, or indeed any cell in any multicellular species, stumbling onto the solution defy enumeration. Yet when one cell managed to do so, natural selection latched onto the solution and propagated it. A freakish event very rapidly becomes the ordinary through natural selection’s ability to “remember” the one success of trillions of failures.
Everything about us arose from the “remembering” of just such freak accidents. Each gene in our body arose when by shear random chance it gave our parent organisms some ability they lacked before. No matter what the odds against any particular gene occurring, given time it will occur. When it does occur, natural selection will not let it disappear.
In the story of the little dog cell with big ambitions we can better intuitively grasp the mechanisms that made us.
I really need to catch up to the rest of the world on reading Gibson.
“No matter what the odds against any particular gene occurring, given time it will occur. When it does occur, natural selection will not let it disappear.”
Either natural selection does not occur at all, or the second statement there is false. After all, if any possible gene will occur, and once having occurred will never disappear, then there is really no selection. This also seems to contradict earlier statements, for instance: “Of all the trillions of cancer cells that mutate each year in every multicellular species on earth, we know of only this one that has succeeded at some time in the last 1000 years.” I take it that success here means stumbled upon a mechanism that allows the cancer cell to survive and reproduce itself outside the original host. But then, that seems to mean that trillions of mutated cancer cells failed, and presumably many of these failures enjoyed unique genetic combinations. Actually, the thrust of the piece appears to be that the odds against any particular gene or combination of genes happening to be reproductively successful are enormous, but it does happen, and often in astonishing ways.
Stephen,
After all, if any possible gene will occur, and once having occurred will never disappear, then there is really no selection.
I think you misunderstood, It is the very process of selection that causes the preservation. Separating the genes that cause themselves to be reproduced from those that do not is the very essence of natural selection. The vast majority of mutations get “forgotten” because they don’t help duplicate themselves. Once a gene does lead to its own duplication (by helping the organism of which it is a part) then natural selection will give it a place at the expense of those other genes who did not. However, once the gene no longer leads to its own duplication, then natural selection “forgets” and the gene starts to fade way.
I take it that success here means stumbled upon a mechanism that allows the cancer cell to survive and reproduce itself outside the original host. But then, that seems to mean that trillions of mutated cancer cells failed, and presumably many of these failures enjoyed unique genetic combinations.
Yes, but being unique doesn’t count. Only being “right” counts. All cancers evolve. Most cancers result from multiple genetic mutations which occur in a series. For each cell whose decedents eventually become a threatening cancer, hundreds of millions die along the way due either to fatal mutation or the bodies anti-cancer defenses.
Its best to think of natural selection as operating like a peg and peg board system. The peg change randomly. If they fit a hole in the peg board, they get copied. Eventually, all the pegs (except those that just mutated) will have shapes that fit them into holes on the board. Change the shape of holes however, and the process starts all over again.
“I think you misunderstood, It is the very process of selection that causes the preservation.” Actually, this is the idea that I was worried might lie behind your claims. There is no process of selection that CAUSES preservation. Various configurations either do or do not survive and reproduce. Those that do wind up being dominant, for a while. That’s pretty much it. There is no “process of selection” as a CAUSAL force.