6 ideas
Noble argues the genome is better pictured as a set of organ pipes that the cell and organism play than as a program that runs the organism. On this view, genes are resources used by higher-level processes rather than a script that determines them. The metaphor is meant to shift attention from the DNA sequence to the system that interprets and deploys it.
Noble proposes that no single level of biological organization, whether genes, proteins, cells, organs or the whole organism, is causally privileged by default. Which level is the right one to explain a function depends on the question being asked and where the relevant interactions are integrated. This rejects the assumption that the lowest level, the gene, is automatically the most fundamental explanation.
Noble argues that causation in organisms runs downward as well as upward. Higher-level conditions such as cell electrical activity, hormonal signals and tissue structure set the conditions under which genes are expressed and proteins behave. He presents these as feedback loops rather than a one-way chain running from gene to phenotype.
Drawing on his own computer modelling of cardiac cells, Noble describes how the heart's pacemaker rhythm is not produced by any single oscillator gene or protein. It arises from interactions among several ion channel currents coupled to the cell's membrane potential. In his models, removing the feedback from cell voltage to the channels stops the rhythm even though all the protein components are still present.
Noble points out that knocking out a gene frequently produces little or no visible change in the organism. He attributes this to redundancy and backup pathways that compensate for the loss. He argues this makes it misleading to say a gene is "for" a function based on the effects of deleting it.
Noble argues that describing genes as "selfish" or as replicators using bodies as vehicles is an interpretive metaphor that cannot be tested against data. He holds that an equally consistent framing treats genes as captives or cooperative components of the organism. His point is that choosing between these framings is a matter of perspective and not something experiments settle.