One of the most striking aspects of DNA is that it uses dimensional representations to encode genetic information into memory. Dimensional semiotic memory utilizes a finite set of iterative (repeating) representations which are recognized in their system by the spatial orientation of each representation. Dimensional semiosis is an incredibly unique phenomenon in the physical world -- with a completely unambiguous physical signature -- but it is yet another easy concept to understand.
There is a fundamental principle within physics sometimes referred to as the minimum total potential energy principle. This principle is related to the Second Law of Thermodynamics, and simply states that any physical object (regardless of its size or composition, as big as a planet or as small as a molecule) will distort and twist, and naturally orient itself to seek its lowest potential energy state. To the average reader, this principle might seem difficult to understand, but it’s a principle we each see in effect around us all the time. For instance, we see it in the way a tree branch covered in snow will hang down low as it counteracts the additional weight of the snow, or the way that the propeller on a toy plane is spun by a tightly wound rubber band until the rubber band becomes loose again. In short, this principle can be thought of in general terms as the natural tendency of any object to seek a balance of all the various forces acting upon it at any given time.
Since all representations are physical objects, they are all subject to this fundamental principle. There are representations that function directly as a result of the medium physically assuming its lowest potential energy state. This includes the vast majority of all informational mediums. A pheromone, for instance, is a perfect example. A pheromone is a chemical compound that serves as a representation by assuming its lowest potential energy state. In other words, any given pheromone is a combination of a certain number of specific atoms that (when bound together as a compound) assumes a certain physical structure according to its nature - and it is that specific three-dimensional structure that the system recognizes and responds to.
However, there is another class of representation whose individuating characteristics (i.e. the properties that make a representation individually recognizable within its system) are not established by the medium assuming its lowest potential energy state. This is a very unique class of representation, and is considerably rarer among all forms of information-bearing mediums. As a simple example, the word “apple” written in ink on a piece of paper is a material structure not unlike the pheromone. In general terms, the atoms that make up the ink will interact with the atoms that make up the paper, and together they will assume their combined lowest potential energy state (i.e. a piece of paper stained with ink markings). However, what is actually recognized within the system is solely the arrangement of the ink markings (the shape and sequence of the letters) and that arrangement has nothing whatsoever to do with the lowest potential energy state of ink and paper. This is to say that the arrangement of the letters could be changed to any number of other arrangements, signifying any number of other messages, with every variation being completely undetermined by the lowest potential energy state of ink and paper. Unlike the pheromone, the pattern of a dimensional representation literally does not have a "physical nature” to assume. Instead, the pattern is imposed on the medium and is therefore independent of the minimum total potential energy state of the medium.
The encoding of information in DNA is exactly such a system. Like the individual characters in recorded language and mathematics, the pattern of nucleotides in each codon of DNA is independent of the minimum total potential energy state of its medium. The pattern itself becomes the causal object in the system, and the primacy of the pattern over the medium results in a representational system with two distinct properties. These two properties are fundamental to an open-ended self-replicating system. First, a finite set of spatially-oriented patterns enables the efficient encoding of virtually any type or quantity of information, subject only to having the appropriate protocols to actualize its effects. Secondly, spatially-oriented patterns (independent of their medium) can be efficiently copied and transferred between mediums, thereby enabling the access and storage of long-term heritable memory. The onset of this representational, open-ended, transferable memory is the primary systematic requirement of Darwinian evolution. It simultaneously establishes a physically-unrestricted genome, while enabling heritable variation. These two capacities place the onset of dimensional semiosis as the necessary physical precursor of Darwinian evolution -- not the product of it. (If A requires B for A to exist, then A cannot be the source of B).
However, dimensional semiosis also places profound additional demands on the organization of the system. Such systems not only require the same transfer protocols as any other semiotic system, but they also require an entirely independent set of purely systematic protocols to establish the dimensional operation of the system itself. These additional parameters include such things as where to start reading along a sequence of representations; in what orientation are the representations to be read, how many individual objects constitute a complete representation, and when to stop reading in order to produce a functional effect. These are not merely theoretical propositions, but demonstrated empirical facts - and without these systematic constraints integrated into the system, the system would simply not function. And because the living cell is an autonomous entity, these additional constraints must be formalized by being be encoded in the sequence of representations they make possible. It is this formalization that enables the autonomy.