Dr Michelle Dickinson: nanotechnologist on whether scientists can build a life from scratch

For centuries, people have argued about what separates something that's alive from something that's simply chemistry. 

Every living thing, from bacteria to blue whales is ultimately made from the same atoms as the rocks beneath our feet. The difference isn't the ingredients. It's how they're organised. 

So how few ingredients can you assemble before chemistry starts behaving like life? 

A team of synthetic biologists have taken a step towards answering that question by building what they call a synthetic cell entirely from carefully chosen chemical components. Published this week they assembled every component themselves, creating a tiny cell-like structure whose complete ingredient list is known. 

The cell can't survive on its own, can't evolve naturally and still depends on scientists to feed it, but it can repeatedly feed, grow, copy its DNA and divide into daughter cells, performing several of the key behaviours we associate with life. 

They carried out a series of experiments, each asking whether one more essential feature of life could be recreated from non-living ingredients. 

Experiment 1 - Can you make an artificial cell grow? 

The researchers began with tiny fat bubbles called liposomes as artificial cell membranes. Inside they placed a carefully designed 90,000-base-pair synthetic genome spread across seven plasmids, along with a purified protein-making system called PURE that could read DNA and build proteins. 

Real cells grow by taking in nutrients, artificial cells can't, so the team invented tiny "feeder" liposomes loaded with fresh proteins, ribosomes, enzymes and membrane material. 

The question was - can one artificial cell feed another? 

To find out, they engineered the synthetic cells to manufacture a membrane protein called α-hemolysin carrying a short histidine tag. Feeder liposomes were coated with nickel-containing lipids that recognised this tag. When the two met, they fused together, delivering both nutrients and fresh membrane material. 

The researchers watched the membranes merge, the contents mix and new proteins begin to appear inside the enlarged synthetic cells. 

Remarkably, the ability to feed wasn't controlled externally, it was encoded by the synthetic cell's own DNA. Cells that produced more of the membrane protein fed more efficiently and grew larger. 

Experiment 2 - Can it repeat the process? 

Growing once isn't life, living cells must grow repeatedly. 

Every 12 hours the synthetic cells were fed, their DNA copied and the population divided before beginning the cycle again. 

The synthetic cells successfully completed five generations of feeding, genome replication and division. 

Each generation produced new DNA, new RNA and new proteins while maintaining much of the original 90,000-base-pair genome. Around 30% of daughter cells still inherited the complete genome after five generations, an impressive result given that the system lacked many of the sophisticated mechanisms real cells use to organise DNA during division. 

Experiment 3 - Can evolution begin? 

This experiment asked whether the synthetic cells could experience something resembling natural selection. 

The researchers deliberately introduced a tiny genetic change. 

One version of the synthetic genome contained a stronger promoter controlling production of the feeding protein α-hemolysin. That meant these cells could produce more feeding proteins, fuse with more feeder liposomes and potentially grow faster. 

They then mixed equal numbers of fast-growing and slow-growing synthetic cells together. 

After just five generations, the faster-growing cells had become the majority. 

When food became scarce, their advantage became even larger. 

The synthetic cells weren't evolving in the full Darwinian sense because the beneficial mutation had been introduced by the researchers rather than arising spontaneously. 

But they were undergoing selection. 

The cells with the more advantageous genome produced more offspring, causing that genetic version to spread through the population, one of the defining processes that shapes life on Earth. 

So... is it alive? 

That depends on who you ask. 

The synthetic cell doesn't yet tick every box that biologists would associate with life. It can't survive without scientists feeding it. It borrows ribosomes from bacteria rather than making its own. And while it can undergo selection, it doesn't yet evolve naturally because the beneficial mutations were introduced by the researchers rather than arising spontane

Episode Transcript

Speaker 1 (00:06):
You're listening to the Sunday Session podcast with Francesca Rudkin
from News Talks.

Speaker 2 (00:11):
It'd be do you know what I mean now, doctor
Michelde can think good morning, good morning. You got quite
a high brown number for us today. I know. It
was just published in biotic dot org and it's a
massive It's one hundred and ninety pages of research. If
you don't read it, just listen for the next five minutes.
And were then basically, can scientists build life from scratch?

(00:33):
A pretty meaty topic. So look what separates something from
being alive from something that is not alive? And it's
literally chemistry, right, because everything from bacteria to blue whales
is made of the same atoms that rocks are, but
rocks are not alive and blue whales are. So the
ingredients are the same, but how they're organizes what makes

(00:54):
something alive or not. And so this amazing study basically
took the ingredients, the chemistry and went can we turn
this into life? Pretty big So what they did is
they took some basically liposomes, which are little flat bubbles
which are what make up a normal cell membrane, and

(01:15):
they try to create an artificial cell and then they
placed inside it ninety thousand base persynthetic genomes spread across
things that we know are in cells, so plasmids and
purified proteins. Basically, they put the ingredients of a cell
into a fake cell, and then they fed them in
some nutrients, and they wanted to know what happens next,

(01:39):
because we've engineered this thing that could be alive. And
as they fed them, they watched these membranes merge and eat,
basically feed each other and grow, and they went, okay,
so this thing is happening, and then they went, well,
can it repeat if we do it more? So they
kept feeding it and the living cells grew, and then

(02:01):
what was interesting is they're DNA copied and they divide
into daughter cells, and they actually produced five generations of
feeding genome replication and division, which basically means five generations
of these types of cells that the scientists invented at
the beginning that then replicated, which you know many of

(02:24):
us would say would be a sign of life. So
then they went, well, if we can create life, can
we create evolution. So they basically made a tiny genetic
change in some of the cells so that some of
them fed better than others, and then they fed them
all and basically they found an evolution like thing, which
is the ones that fed better grew faster and replicated faster,

(02:48):
and therefore it wasn't full Darwinian but basically survival of
the fittest. Those that could eat better basically survived more
and duplicated more. And so you go, okay, well, these
are all the things that we consider to be life.
So did we just make life with chemistry? And the
answer is we don't know, basically, but it's massive and

(03:09):
basically we've used synthetic ingredients to create a cell that
replicates and feeds and does a lot of the things
that normal cells do. Now, these cells can't survive on
their own. They're not at that point yet. But I
do think it's an interesting question around what is alive
and what is not. And this might be a really
silly question, but is it evolution of humans have instigated

(03:31):
it rather than hitmen naturally? No? Totally, I mean no,
technically not. But because these things can't happen naturally, the
only way to imply that there would be a natural
selection would be to credit change and then give them
both the same thing and see if one would selectively
be better and the answer is yes, but it's not
classed as evolution technically, although if these been naturally out there,

(03:53):
we would. And I think what is really interesting is
it's not about whether or not we've created life. I mean,
I don't think we have. We've created some of the
traces of it, but it's actually the first time that
we've gone well, which parts of chemistry are absolutely essential
for life, and I don't think we've ever known that before.
And that's the difference between a rock and a blue whale.

(04:14):
And so if you have time to read one hundred
and ninety pages of this very deep article, which I did,
it's fascinating if you don't. Basically, we've blaunted some chemistry
and it's been really interested. I think we can back
calculate now for medical reasons, how sales interact and what
they need to grow and survive.

Speaker 1 (04:33):
You know, that's fascinating.

Speaker 2 (04:34):
Thank you so much, Michelle, really appreciate that. We'll talk
next week For.

Speaker 1 (04:38):
More from the Sunday session with Francesca Rudkin. Listen live
to News Talks it Be from nine am Sunday, or
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