Suppose you wanted to know how simple life can possibly be. Not life as we usually meet it, with its brains and wings and roots, but life at the floor: the least a thing can have and still be alive. Craig Venter’s team asked exactly that question, and they asked it the hard way.
They took a bacterium and began removing its genes, one at a time. Remove a gene, then see whether the cell still lives and still reproduces. If it does, remove another. Keep going until the cell can no longer survive, then back up a step. It took them years.
The Floor
The floor was 473 genes.
Below that number, the cell could not live and copy itself. Four hundred seventy-three genes, each one a stretch of coded instructions, all working at the same time in a coordinated way, is the minimum this team could reach for a living, reproducing cell.
Let that settle for a moment. The simplest life we know of is nowhere near simple. A single bacterial cell, stripped of everything it could spare, still carries hundreds of genes that must cooperate for it to exist at all.
The Part That Gets Me
Here is the detail I cannot stop thinking about. Of those 473 genes, the researchers still do not know what roughly a third of them do.
Consider what that means. We did not design this cell. We cannot fully read it. We know only that if you take those mysterious genes away, the cell dies. The minimal cell carries instructions that the team who produced it cannot yet explain, and the cell needs every one of them.
Deleting Is Not Building
Notice, too, how they got there. They did not assemble a cell from scratch. They started with a cell that already existed, already alive and already reproducing, and they subtracted. Every step of the project depended on a working cell being there first.
That is a very different thing from explaining how the first cell came to be. Removing parts from a running engine until it stalls tells you how many parts the engine needs. It does not tell you how the engine was built, and it certainly does not show that the engine built itself.
I spent twelve years trying to argue myself out of belief in God, and the cell was one of the places where I failed. I kept finding information there: coded, stored, and translated, and I have never known a code to write itself. When the simplest possible living cell still needs hundreds of genes working together, and a third of them are still beyond our understanding, the honest response is not confidence that chemistry stumbled into it. The honest response is awe, and a question about who wrote the instructions.
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