The Limitless Potential of Biological Systems
Imagine a world where we understand exactly how biology works. How every gene is controlled, how every ligand docks, how every protein folds. Imagine a world where we can manipulate biology freely and predict the full implications with molecular precision. A world where we can build arbitrarily complex biological systems from the ground up.
What could we build, with the tools of biology at our disposal?
There is a field called synthetic biology that is already tackling this question. Synthetic biologists try to reverse-engineer biological systems, modify them, and ultimately make them from scratch. There is a ton of cool stuff happening in the field (for example, scientists are creating synthetic bacteria with altered genetic codes). However, the tech world’s perception of synthetic biology is predominantly shaped by conversations happening at its intersection with business and startups.
This industry chatter currently centers around harnessing synthetic biology to make manufacturing and agriculture more sustainable and efficient, to make clothing and materials with new advanced properties, and to produce new therapeutics. Biological systems (usually E. coli or yeast) are likened to little factories that we can coax to produce whatever we desire.
Make no mistake, these are all incredible commercial applications, which will do no small part to improve society, aid global warming and cure disease. What is happening in the industry and what is now on the cusp of commercialization is tremendously exciting, and I highly recommend you check out thought pieces like a16z’s Biology is Eating the World.
But my inner nerd can’t help but feel that the current zeitgeist of biological applications doesn’t capture the full potential of biological systems, not by a long shot. Biology is capable of so much more.
To show you what I mean, let’s look at the hidden power of a single biological cell.
If you went through high school biology, your mental image of a cell is probably something like this:
It’s easy to nod at this image, memorize some facts about the different organelles (“the mitochondria is the powerhouse of the cell!”) and then move on.
I’m really partial to this animation of a proton pump, one of the many proteins embedded in the membranes of the cell. It’s a reminder that behind the static images of cells, there is a dense, dynamic world of complex little machines. Behind every cellular property and process, there is a mechanism, a deeper level to explore and understand.
Tuck that thought in the back of your head and let’s turn our attention to a very special cell, the zygote, which forms when an egg is fertilized with a sperm. Each of us human beings came from one of these.
Think about the numerous steps that this tiny zygote must go through to finally become you. The first steps look like this:
Then the rest of the baby happens somehow.
Again, it’s easy to take for granted that all these steps just happen, but remember that little protein animation from earlier and the fact that every cellular process has an underlying molecular mechanism. Let’s ask some questions.
How, for example, does a particular cell know where to go and what to do? How does this mass of cells we call an embryo manage to self-assemble, when there is no external observer to coordinate the cells and tell them what to do? What is the mechanism behind that? What kinds of proteins and molecules are involved?
The short, one-line answer is that cells use a bunch of clever tricks like chemical gradients, local cell-to-cell communication and adhesion, and complex feedback loops to coordinate with their neighbors, understand their orientation, and update their internal state (e.g. their DNA) to traverse their unique path of cellular differentiation, providing the building blocks for development to occur.
Having some notion of what the building blocks of development might look like, we now ask: how does development manage to be so orderly and predictable? Why don’t we sometimes end up with three arms instead of two, because a signaling molecule happened to float the wrong way and accidentally hit the wrong protein, causing a cell to change its developmental trajectory and become an extra arm? Why don’t these accidents happen all the time?
One answer, although it is hardly satisfying, is that there must be a variety of cellular safeguards and failsafe mechanisms at every step of the way to ensure that development only happens the way it is intended to.
The point here isn’t to answer these questions in detail, but to guide you towards a visceral feeling of the sheer complexity of the process of embryonic development.
At one point, your hand, with its delicately crafted bones, its muscles and tendons, its web of veins, its keratinous nails and its little hairs, was a single cell. This cell divided and divided, and its daughters moved and transformed and further divided in a precise and highly choreographed dance. At some point, a cell had to decide to become a knuckle. At some point, a cell had to leave its four cousins to become a thumb. Each of tiny step of this process, every cell movement and cell transition, was guided at the molecular level by chemical gradients and signals and protein interactions, and tightly controlled by cellular guardrails. At the other end of this impenetrably byzantine process is your familiar, dependable, five-fingered hand.
There are some 40 trillion cells in your body right now, and the process of development guides them each to their proper place. This process, which happens routinely with each generation of life, is the most complex process on our planet.
And that’s not even the craziest part. The craziest part is that this entire developmental process happens in isolation, without outside interference, starting from a single cell. Which implies that every single aspect of this unfathomably complex process, every stimulus and response and safeguard, must have its origin in that original cell.
The precise shape, length, and orientation of every one of your bones and muscles. The complex macrostructure of your four-chambered heart, your alveoli-laden lungs, your sentience-bearing brain. Your capacity to acquire language and feel love. Every single detail of your biological structure and function, from the big to the small, is encoded and compressed in some form in the DNA and proteins of that single 0.1mm zygote cell from which you came.
The ability to precisely and reliably express living beings of unbelievable complexity — that is the power of a single cell.
A single cell can contain the programming to reliably create an entire human being, from scratch. And this capability developed by chance, over millions of years of evolutionary pressure.
What could we build if we could direct the expressive power of biology intentionally?
I’ll offer a few whimsical examples, just to kick things off.
Perhaps we will build living bio-homes, whose roofs can gather energy via photosynthesis, whose kitchens bear fruit directly from the walls. Apply a chemical signal to the wall of your house, and it will grow a new bedroom or sprout a patio deck.
Perhaps there will a new profession of biological engineers whose job is to program various objects into genetic code. You‘d download the code for a chair off the Internet, synthesize the DNA at home, inject it into the floor of your bio-house and form a new “zygote” in your living room floor, which in 24 hours will go through various developmental stages to produce a new leather-backed bio-armchair. The home becomes a new mode of distribution, a bio-platform for growing anything that humans can imagine, without the need for supply chains or Amazon Prime delivery.
Perhaps our very cities will be massive living organisms. Living streets will be self-cleaning and automatically break down litter. Streets and neighborhoods will organically shift and adjust as the needs of a city change.
Perhaps we will each become shapeshifters, able to morph and modify our bodies overnight, growing wings to fly or gills to explore the oceans and shedding them at will. Photosynthetic pigments in our skin will make food optional. Aging and disease will have long since been abolished.
And this is only the beginning. What human ingenuity will do with the tools of biology, and what the world will ultimately look like, I haven’t the slightest inkling.
We are, of course, very far from this future.
You only have to look at the failure rate of drug development (over 90%) to know that our understanding of biology is still in its early days. The challenges of decoding biology are unspeakably immense, and the consequences of rushing ahead can be disastrous. We should not, in our haste to master biology, make reckless, irreversible decisions while our understanding is still incomplete. Nor should we downplay the incredible innovations that synthetic biology will achieve in the near-term.
My goal here is not to proclaim that the bio-singularity is 50 years away. Rather, my goal has been to share with you a bit about why biology excites me, a bit of the sheer wonder I feel when I think about the mechanistic underpinnings of biological systems, and the hidden potential I see in the living things we largely take for granted. If I’ve awakened in you a new appreciation or curiosity for biology, I shall be glad.
Nature has, through 3.6 billion years of chaotic innovation, developed an incredibly advanced nanotechnology that we refer to casually as biology. Demonstrations of this technology are all around in us, in the incredible array of living organisms that populate our planet. Our understanding of this otherworldly technology slowly accumulates, thanks to the sweat and toil and relentless pipetting of biologists around the world.
The next time you look in the bathroom mirror, remember this: you are the most advanced technology that has ever walked the earth.
There is magic in the world if you know where to look.
