Organisation And The Origin of Life
Biochemists have long imagined that autocatalytic sets can explain the origin of life. Now a new mathematical approach to these sets has even broader implications
One of the most puzzling questions about the origin of life is how the rich chemical landscape that makes life possible came into existence.
This landscape would have consisted among other things of amino acids, proteins and complex RNA molecules. What’s more, these molecules must have been part of a rich network of interrelated chemical reactions which generated them in a reliable way.
Clearly, all that must have happened before life itself emerged. But how?
One idea is that groups of molecules can form autocatalytic sets. These are self-sustaining chemical factories, in which the product of one reaction is the feedstock or catalyst for another. The result is a virtuous, self-contained cycle of chemical creation.
Today, Stuart Kauffman at the University of Vermont in Burlington and a couple of pals take a look at the broader mathematical properties of autocatalytic sets. In examining this bigger picture, they come to an astonishing conclusion that could have remarkable consequences for our understanding of complexity, evolution and the phenomenon of emergence.
They begin by deriving some general mathematical properties of autocatalytic sets, showing that such a set can be made up of many autocatalytic subsets of different types, some of which can overlap.
In other words, autocatalytic sets can have a rich complex structure of their own.
They go on to show how evolution can work on a single autocatalytic set, producing new subsets within it that are mutually dependent on each other. This process sets up an environment in which newer subsets can evolve.
“In other words, self-sustaining, functionally closed structures can arise at a higher level (an autocatalytic set of autocatalytic sets), i.e., true emergence,” they say.
That’s an interesting view of emergence and certainly seems a sensible approach to the problem of the origin of life. It’s not hard to imagine groups of molecules operating together like this. And indeed, biochemists have recently discovered simple autocatalytic sets that behave in exactly this way.
But what makes the approach so powerful is that the mathematics does not depend on the nature of chemistry–it is substrate independent. So the building blocks in an autocatalytic set need not be molecules at all but any units that can manipulate other units in the required way.
These units can be complex entities in themselves. “Perhaps it is not too far-fetched to think, for example, of the collection of bacterial species in your gut (several hundreds of them) as one big autocatalytic set,” say Kauffman and co.
And they go even further. They point out that the economy is essentially the process of transforming raw materials into products such as hammers and spades that themselves facilitate further transformation of raw materials and so on. “Perhaps we can also view the economy as an (emergent) autocatalytic set, exhibiting some sort of functional closure,” they speculate.
Could it be that the same idea–the general theory of autocatalytic sets–can help explain the origin of life, the nature of emergence and provide a mathematical foundation for organisation in economics?
As Kauffman and friends say with just a little understatement: “We believe that these ideas are worth pursuing and developing further.”
We’ll look forward to following the work as it progresses.
Ref: arxiv.org/abs/1205.0584: The Structure of Autocatalytic Sets: Evolvability, Enablement, and Emergence