Can life come from non-life?

Nothing to copy from

Can life come from non-life? Every living thing you've ever seen came from another living thing. But the very first cell had no parent. There was nothing before it to copy from.

So where did it come from? The Bible's answer is that life comes from the living God, and we'll open that answer at the end. First, ask the chemists who have tried to make a cell from scratch, and see how far they've come.

Sources:The origin of life (abiogenesis)

Sparks in a flask

In 1953, a young chemist named Stanley Miller filled a glass flask with methane, ammonia, hydrogen, and water vapor. Then he ran electric sparks through it for about a week, like lightning. He got a few simple amino acids, such as glycine and alanine, the building blocks of proteins. It was a famous result.

Scientists now think the early air was mostly nitrogen and carbon dioxide, not Miller's mix. But either way, a few building blocks are a long way from a living cell. A pile of bricks is not a house.

Sources:Miller, “A Production of Amino Acids Under Possible Primitive Earth Conditions,” Science 117 (1953)Lazcano and Bada, “The 1953 Stanley L. Miller Experiment: Fifty Years of Prebiotic Organic Chemistry” (2003)Cleaves et al., “A Reassessment of Prebiotic Organic Synthesis in Neutral Planetary Atmospheres” (2008)

All or nothing

Here's how long a way. Even the simplest cell needs three things at once:

• DNA, to store the instructions.
• Proteins, to read and copy the DNA. But DNA's instructions are what build those proteins.
• An oily skin to hold it all together, made by those same proteins.

Take away the DNA, and there's no recipe for new proteins. Take away the proteins, and nothing reads the DNA or makes the skin. Take away the skin, and everything drifts apart. Lose any one, and the cell doesn't work. It's all or nothing.

One answer is an RNA world: an earlier, simpler world of RNA that broke the circle, with RNA both storing the instructions and doing the work. In 2009, chemists at Scripps did make two RNA enzymes that copy each other. But they designed them first, and fed them ready-made pieces of RNA. Nobody has shown how early-earth chemistry could build those pieces and link them into such an enzyme. And RNA's own sugar, ribose, is one of the problems a synthetic chemist names below.

Sources:The central dogma: DNA, RNA, and proteinThe cell membraneThe RNA worldLincoln and Joyce, “Self-sustained replication of an RNA enzyme,” Science (2009)

“Almost a miracle”

How small can a cell get? In 2016, scientists cut a bacterium down to the fewest genes it could live on: 473. They still couldn't say what 149 of them do. And they didn't build a cell from scratch. They made its DNA and put it into a cell that was already alive.

You don't have to be a Christian to see the problem. Eugene Koonin, an evolutionary biologist at the U.S. National Institutes of Health, writes that the “origin of life is a chicken and egg problem”: before anything can copy itself, you already need the machinery that does the copying. And Francis Crick, who shared a Nobel Prize for finding DNA's double helix and was a firm skeptic of religion, wrote:

“An honest man, armed with all the knowledge available to us now, could only state that in some sense, the origin of life appears at the moment to be almost a miracle.”

Francis Crick, Life Itself (1981), p. 88

Neither man turned to God. Look where their answers went instead. Koonin said that in an infinite multiverse, even this would happen somewhere by chance. Crick suggested that aliens sent life here on purpose. But Crick only moved the question to another planet. And Koonin reached for the same multiverse we met in Part 2, with no more evidence for it here.

Sources:Hutchison et al., “Design and synthesis of a minimal bacterial genome,” Science (2016)The minimal cell (Mycoplasma laboratorium)Koonin, Biology Direct 2:15 (2007)Crick, Life Itself (1981), p. 88Crick & Orgel, “Directed Panspermia” (1973)

Ask a synthetic chemist

James Tour builds complex molecules for a living at Rice University, even tiny molecular “nanocars.” He has studied the attempts to make life from scratch, and he names three problems.

First, the building blocks. Made without a living cell, they come out as messy mixtures. In one of the best attempts to make ribose, the sugar in RNA, the form chemists wanted was about fifteen percent of the result. It was tangled with twenty-two other compounds they could identify, and more they couldn't.

Second, handedness. Many of life's molecules, like the amino acid alanine, come in left- and right-handed forms, and life uses only one. Tour puts it simply:

“Their mirror images cannot do their work.”

James Tour, “Animadversions of a Synthetic Chemist” (2016)

Without a cell, chemistry gives you both hands, mixed. Nobody has shown how early-earth chemistry could make just one.

Sources:James Tour, “Animadversions of a Synthetic Chemist,” Inference 2, no. 2 (2016)Shapiro, “Prebiotic ribose synthesis: a critical analysis” (1988)Homochirality

The dream team

Third, putting it together. Even with every pure part in hand, nobody knows how to assemble them into something alive. Tour pictures handing the world's best scientists everything, already made and perfectly pure, and asking them to build a living system: “Give the dream team polymerized forms: polypeptides, all the enzymes they desire, the polysaccharides, DNA and RNA in any sequence, cleanly assembled. Ready now? Apparently not.” And his verdict:

“Those who think scientists understand the issues of prebiotic chemistry are wholly misinformed. Nobody understands them. Maybe one day we will. But that day is far from today.”

James Tour, “Animadversions of a Synthetic Chemist” (2016)

He leaves room for tomorrow: “Maybe one day we will.” But a hope for tomorrow is not evidence today. As things stand, chemistry alone has never been shown to make a cell.

Sources:James Tour, “Animadversions of a Synthetic Chemist,” Inference 2, no. 2 (2016)

A code in every cell

And here's what chemistry would have had to write. DNA is a code: four letters, read three at a time. Each three-letter word means one building block of a protein. This is the real start of the gene for hemoglobin, which carries oxygen in your blood:

• ATG: start
• GTG: valine
• CAT: histidine
• CTG: leucine
• ACT: threonine
• CCT: proline
• GAG: glutamic acid

Your ribosomes read six to nine words a second, and misread only about one in a thousand to one in a hundred thousand. Change one letter of the seventh word, GAG to GTG, and glutamic acid becomes valine. Inherit that one typo from both parents, and you have sickle cell disease.

The code itself is remarkably good at softening typos like that one. Scientists compared it with a million random codes, and only about one of them did better than the real one.

DNA works like software: a written message, read by machines, using a lookup table. Software is written in 0s and 1s and run by a computer. DNA is written in A, C, G, and T and read by ribosomes. And every code we've ever traced back to its source came from a mind. That last step is an inference, not a lab result. But it follows the evidence we have, and the Bible names the mind.

Sources:The human hemoglobin gene, HBB (NCBI)The genetic codeTranslation: how ribosomes read the code, how fast, and how often they slipSickle cell diseaseFreeland & Hurst, “The genetic code is one in a million” (1998)