Sixty-year-olds don't often have children, but we are
witnessing the birth of a new field of engineering made possible by the
marriage of two discoveries that date from the 1950s: DNA and the integrated circuit. In a recent article in the San Jose Mercury News, Emily Leproust, CEO of Twist Bioscience, is
quoted as saying that her company can manufacture DNA to order, letter by
letter. They do this by using
advanced microstructures and computing power made possible by the
semiconductor-chip revolution to synthesize DNA based on concepts drawn from
the latest biological discoveries.
According to her claims, the possibilities, as the saying goes, are
endless: everything from
tailor-made vaccines targeted at the latest flu-virus strain to weirder ideas
like nice-smelling bacteria to grow on your skin as a perpetual perfume. But is this capability really
"designing life from scratch," as the headline claims? And will it really lead to the kinds of
radical advances in manufacturing and materials science that its promoters are
talking about, without opening the door to some dire consequences as well?
First, we should get straight what companies like Twist
Bioscience are really doing. Say
you're a biologist who wants a particular genetic sequence for some reason or
other. In the past, you'd have to
find large chunks of what you want lying around and splice them together, sort
of like editing a documentary video out of existing footage. A lot has already been done in this way
under the general name of genetic engineering, leading to things like disease-resistant
crops, fluorescent fish in bright artificial colors, and so on. But what Twist Bioscience and similar
firms are doing is more like making an animated film, frame by frame. Each frame (i. e. letter in the genetic
sequence) can be whatever you want, and so you can literally get whatever gene
you ask for.
The problem in this novel situation is knowing what to
ask for. And here's where we have
to stand back at the designing-life-from-scratch claim and think twice about
it.
No
engineering design is truly de novo—totally
original—if for no other reason than the designer has to remain within the
constraints of the physics and mathematics of what is possible to design. If your bridge design ignores the rated
strength of the materials used in its construction, it's likely to fall
down. Making DNA that will do a
prescribed task in a living cell is a highly constrained problem—constrained by
the existing design of the target cell.
Currently, we have adequate (but probably not exhaustive) knowledge of
the functions of only a few types of cells—bacteria, mostly—knowledge that is
enough to allow us to manipulate their machinery with custom DNA to do things
we want. But we didn't design the
cells that the synthetic DNA is going into.
Most people not handicapped with a Ph. D. can see that
there is a Designer behind the unfathomably complex thing that is biological
life on this planet. No human
being can claim to have designed an existing cell from scratch. Clients of Twist Bioscience ordering
their customized DNA molecules are like programmers who have laboriously
learned an operating system language and are now ready to program a computer
they had no hand in designing. As
every coder knows, one little comma in the wrong place can wreck the whole
program, and that is why checking and accuracy are so important to DNA
synthesis—cells can be as unforgiving as computers when it comes to mistakes.
Fortunately, most mistakes along these lines simply die,
or fail to achieve the goal that the designer aimed at. But along with all the wonderful
promises of fantastic new materials comes the downside question: when and how will the ability to
synthesize DNA be used for evil as well as good?
And some answers to that question might not be as simple
as the melodramatic picture of some anarchic radical cooking up a
kill-everybody-in-sight germ in his secret laboratory. Take one of the ostensibly good
predictions touted by synthetic DNA's promoters: the ability to make bacteria that would crank out meat and
milk without the tedious inconvenience of raising cows or pigs or chickens.
Suppose synthetic milk that is every bit as good as the
real thing becomes something you could do in a chemical plant for one-tenth the
cost of the way dairy farms do it.
The dairy farmers would immediately find themselves in the position of
slide-rule manufacturers when the first cheap electronic calculators hit the
market. Only there are a lot more
dairy farmers around the world than there were slide-rule makers. To a dairy farmer, this so-called
advance that the synthetic DNA promoters call a good thing, looks a lot like an
evil thing. Unless some social or
governmental factor intervenes, the dairy farmers would simply be out of luck
and would have to find some other way to make a living.
This situation reminds me of one of the best classic
Ealing comedies of the 1950s: the
Alec Guinness film "The Man In the White Suit." It was made at a time when postwar
industrial Britain was feeling threatened by technological advances. The story concerned a nerdy chemist
played by Guinness who discovered a way to make a type of cloth that never
stained, never tore or wore out, and appeared to be capable of lasting
forever. His escapades with
unsympathetic managers, union leaders, and other interested parties lead both
to some hilarious scenes, and also to a serious point, encapsulated in an
encounter he has toward the end of the film with an old, broken-down woman who
ekes out a living taking in washing.
Having heard of his invention, she confronts him and asks, "What
about me bit of washin', eh?"
What, indeed.
The film avoided a serious answer to this question
(spoiler alert!) by giving the cloth a shelf life of only a month or so, and
when all existing samples self-destructed, life went back to normal. But we may not have such an easy out
with the products of synthetic DNA. Throughout history, ways of life have come and gone in
response to technological advances, and at this time, it doesn't seem that
synthetic DNA is about to plunge us either into a secular Paradise or Hell on
earth. But as its products prove
themselves in the marketplace and begin to disrupt older ways of doing things,
we may have to decide where designing ends and meddling begins.
Sources: The article "Designing
life from scratch: A fledgling field is about to take off" by Lisa M.
Krieger appeared on Aug. 8, 2015 on the San
Jose Mercury News website at http://www.mercurynews.com/science/ci_28608185/designing-life-from-scratch-fledgling-field-is-about. I also referred to the Twist Bioscience
website at www.twistbioscience.com, the Wikipedia articles on recombinant DNA
and artificial gene synthesis, and the Internet Movie Database article on
"The Man In the White Suit."
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