The idea was daring, radical—dangerous even. Is it possible to build a living organism from scratch that’s smaller, simpler, more bare bones than anything now alive? Can we outsimplify nature itself and maybe get a peek at the raw machinery—nature’s secret formula—for the essence of life?

We—you and I—are dense with working parts. A human cell has more than 20,000 genes, fruit flies 13,000, yeast cells 6,000. But if we look for the simplest creatures on the planet, we will find a wee bacterium that lives happily in the digestive tracts of cows and goats: Mycoplasma mycoides.

It builds itself from a very modest blueprint—only 525 genes. It’s one of the simplest life-forms we’ve ever seen.

So, suggested Craig Venter eight years ago,