Our cancerous common ancestor?

Paul Raven @ 18-03-2011

Peter Watts, still recovering from a close brush with mortality in the form of a flesh-eating virus (pictures NSFL – Not Safe For Lunch), blogs an interesting new scientific paper that suggests that we are all cancer. Take it away, Mister Watts:

I don’t mean this proximally. I mean it in the sense that all birds are dinosaurs — because according to Davies & Lineweaver, cancer (more precisely, “tumor-like neoplasms”) is the common ancestor of all animal life. Every malignant lump on your breast, every metastatic colony proliferating through your marrow, is just a rebooted revisitation of your grandmother a million times removed.

The basic idea’s petty straightforward. Natural selection reaches into every corner of the biosphere, you see; and a billion years ago that meant every cell for itself because unicellular life was the only game in town. A mere six hundred million years back, though, all that had changed. Metazoans were everywhere — cells grouped into colonies with specialized subsystems called tissues and organs —and somehow, within those colonies, the whole beat-the-competition thing had fallen out of favor. Cells worked together, now; hell, red blood cells even gave up their nuclei for the good of the organism, which really puts the kibosh on any future solo career. I think it had something to do with inclusive fitness.

In between, presumably, there was something halfway between Cuba and the US, some intermediate form between everyone for themselves and everyone for the state. Some kind of loose affiliation of cells which valued their individual freedom, but were not above at least some level of cooperation. Modern-day sponges might be a pretty good example: some cellular specialization, a bit of the ol’ helping hand between cells, but nothing so altruistic as an actual tissue. Call it “Metazoa 1.0″. Davies and Lineweaver do.

According to D&L, that old 1.0 operating system is still sleeping down there in our genetic code; it’s just been turned off by the more recent regulatory genes of Metazoa 2.0. It hasn’t been eradicated outright, because a lot of those ancient genes are still useful (“…the genes responsible for the cellular cooperation necessary for multicellularity are also the genes that malfunction in cancer cells.”) It’s just been — tamed, is as good a word as any. Tamed, and deactivated.

Except when something happens to one of those bits of regulatory code that keep it comatose. When some base pair flips this way instead of that, Metazoa 1.0 wakes up, its ancestral toolkit intact, ready to party like it’s One Billion Years B.P.

Watts, trained scientists that he is, is at pains to point out that Davies & Lineweaver are merely looking at old data with a new interpretation, and that they’ve put forward a theory rather than a statement of fact… and yeah, I know most of you who read here already know the difference, but this is the internet, after all. But…

… the great thing about being a science fiction writer is that I don’t really have to wait if I don’t want to. Here is an idea, peer-reviewed and legitimately published, thrown into discourse: We are all descended from Cancer. We are borne of the Holy Tumor. Isn’t that a thought. Doesn’t that get your mind going: to the imagination of ancient habitats, somewhere on this planet or within it. To isolated refugia, cut off from the rest of the world when stromatolites were still young, where 2.0 never happened and the cancerous Metazoan prototype was free to chart its own evolutionary course through a billion years.

I find these sorts of insights into the genesis of story ideas fascinating (as I do the science at the root of them). Though I’m kinda surprised that a guy who was nearly killed off by some incredibly virulent and weird disease a few weeks back (on the tail of having narrowly avoided becoming an anomalous Canadian blip in the 2010 immigration law incarceration statistics of the United States) needs to read biology papers to find potentially horrifying things to write about…