How simple can life get?

The New Scientist for April 2nd announced the design and making of a bacterium with the smallest ever set of genes. Some will infer that life-in-a-test-tube is possible.

Life forms are too complex for life to arise spontaneously, with interdependent systems just springing forth unaided. How simple a living thing is it possible to get? Certainly it would need to be a single-celled creature such as a small bacterium.

In April 2016, The Venter Institute published details of the smallest genome that would support life under ideal conditions. First Craig Venter’s team designed a basic set of genes on a computer. Then they took a small bacterium and painstakingly removed single genes, one at a time. Where the bacterium survived such a removal, that gene could safely be discarded from the genome. They finished up with a tiny genome of only 473 genes. They removed its own genome from a bacterium and replaced it by this minimal genome, nurturing it in a dish of easy-to-process glucose for energy. The synthetic genome then used the machinery of the cell to grow and divide like any living cell.
This remarkable piece of genetic research is very different from making life from scratch, and only serves to highlight the problems involved. The team used naturally occurring genes – they are far and away too complex to design and form from scratch. Moreover, these leading geneticists had no idea what was the function of a third of the genes found to be indispensable to life. The rest of the genes coded for proteins vital to life and checked the fidelity of genome duplication when the cell divides, or made the machinery for turning nutrients into energy. The nutrient rich environment enabled the minimal genome to survive without other genes needed in a harsher situation. The rest of the cell was a ready-made bacterium with all its natural components.

Far from shedding light on how life arose without a designer, the exercise highlighted our lack of knowledge of many cell functions. How could even a genome of less than 500 genes spring from non-living material? Venter’s team have demonstrated that life needs a living Maker.