(containing the genes in a classical sense) and some proteins are multifunctional. Which effects will be realized depends on a multitude of other factors, and sometimes on spatial information as well, i.e. on the place within the cell or a multicellular network. Some genes overlap, some genes can be spliced in multiple ways, depending on the situation, and the resulting RNA variants will lead to different proteins that are all related to the same DNA stretch. Sometimes the cell uses fractions of one and sometimes fractions of the other of the two single DNA strands as a template for producing a functional RNA. There are also switches to alternative reading frames, i.e. the shifting of the three-letter code by one, resulting in different sequence information. There is sometimes even post-transcriptional editing of mRNA, i.e. the introduction of changes in the sequence of an mRNA molecule after its composition, which also leads to a different amino acid sequence of the protein being built from it [14, 19-22]. Genes are multifunctional [23], and therefore they can no longer be considered as independent factors in a chain of events. But this is precisely what the idea of the ‘genetic program’ suggested.
Taking these and other phenomena into account, Eva Neumann-Held [24] has reconsidered the very concept of the gene from a systems perspective. If we still want to call what explains the biosynthesis of a particular type of protein in a cell a ‘gene’, we can no longer say that one stretch of DNA is responsible. It is rather a range of factors, interacting with DNA and with each other, and processes sometimes transgressing the boundaries of the cells and the body, that are actually contributing. This set of contributing factors includes DNA, but also much else. Neumann-Held bases her reflection on a groundbreaking book by Susan Oyama from 1985 that has the title ‘The Ontogeny of Information’ [25] and has inspired many authors to new formulations under the umbrella term of a ‘developmental systems approach’ [26, 27]. The key idea was a new attempt to theorize development. Previously, we thought development was basically a result of two different information resources, one internal and genetic, the other external, i.e. social, environmental, or cultural. The divide between these two information resources has materialized in the ‘nature or nurture’ debate in developmental psychology. One school emphasized the genetic contributions (sociobiology, evolutionary psychology, etc.), the other more the social and cultural factors. Oyama's point was that development is better seen as an interaction of both, but not in the sense of an interaction between two independent types of factors. There can be no genetic factors without the environment, and there can be no environmental factors without an organism and its internal resources. Both are mutually related, so that we should avoid making a distinction between those two classes of contributing factors. From this, Oyama came to a different understanding of genetic information as developmental information. Developmental information itself has a developmental history. With reference to Gregory Bateson's [28] famous definition of information as ‘difference that makes a difference’, she explains: Genetic information ‘neither preexists its operations nor arises from random disorder. … Information is a difference that makes a difference, and what it “does” or what it means is thus dependent on what is already in place and what alternatives are being distinguished’ [25, p 3].
Genetic information, in the sense of developmental information, is itself'developmentally contingent in ways that are orderly but not preordained, and if its meaning is dependent on its actual functioning, then many of our ways of thinking about the phenomena of life must be altered’ [25]. Following this line of thought, biology's basic picture is being transformed.3
The program view assumed that the development of the complex organism we see in the biosphere depends on the existence of genetic information, which can be copied and reproduced from a template. It said that the generations do not transmit a small prototype or the adult structure to the next generation, and no supernatural intentions or forces are necessary for a comprehensive explanation of the development of a new generation. What is transmitted is a list of instructions for making that structure [29, p 2]). The systems view by contrast sees that in fact it is the entire cell that is reproduced, not only some lists of instructions. The cells reproduce not because the genome contains instructions for building it, but
‘because any inheritance involves passing on DNA and all the cellular and extracellular structures, processes, and materials necessary for its exploitation’ [25, p 77].
Information can therefore be seen in at least two different ways: either as something inherent in a pattern that is transmitted or as something that is itself a product of interactive dynamics. Accordingly, two different ontologies of living phenomena are put forward.
But they are not equivalent offers, from which we could choose one arbitrarily. There are today serious reasons for preferring the systemic approach. The most compelling of these comes from science itself.
If information for development is a product of interactive dynamics, it does not exist before the development of the system actually takes place. Developmental information continually emerges from the interactive dynamics of the cellular (or multicellular) system and – we need to allow this conclusion as well – continually fades away afterwards. In this sense, genetic information is contingent and ephemeral. DNA is an inert and relatively constant molecule, a source of stability for the system and highly important in many ways, but DNA is not the carrier of developmental information. We can say that the organism is essentially a self-informing system. The whole system develops and behaves regularly and predictably in many ways, but the regularity is not a result of a preexisting program.
This theoretical rereading of the molecular evidence in terms of systems cannot take away any of the empirical evidence that we have about the causal involvement of DNA sequences or mutations in the development of certain characteristics like diseases. The systems view, as I understand it, is not an argument against genomics, medical genetics or against DNA-related research in any way. The argument does not work on the level of experiments or empirical work, but on the level of the interpretation of the empirical evidence, which can be seen as plausible or implausible.
Who Is the Author of the Genetic Text?
The impact of the systems approach and of reinterpreting genetic information reaches beyond criticizing the genetic program metaphor. It contains also a critique of other metaphors that are used to explain the meaning of genomic information in terms of signs contained in DNA sequences: the book of life, the instruction book, the architecture plan, the blueprint, the text, and related ones, in other words all metaphors that work with a difference between signifier and signified and introduce a semantic relation between DNA as a ‘sign for’ and the meaning of this sign. Sign metaphors do not work within a systems approach because they presuppose that information for development preexists.
The assumption of preexisting meaning in organisms would also be difficult to defend from a hermeneutic point of view. Signs or compositions of signs (texts) that we use in language are not just prints on paper that can be copied or transformed by certain rules. Because they belong to language, texts are expressions of personal life. In contrast to spoken language, they are permanently fixed expressions of personal life. Language, as Gadamer puts it, is the universal medium of understanding,
