The title of the article is somewhat misleading. David Sinclair emphasizes in this book Life Span that there is no gene for ageing. Rather, ageing can be understood as an outcome of the second law leading to molecular chaos at the level of DNA related molecules. He also emphasizes that epigenesis correspond to informtion processing in continuous degrees of freedom related to DNA geometry. In TGD these degrees of freedom would be associated with the magnetic body (MB) carrying dark matter as heff=nh0 phases of ordinary matter and responsible for control and induction of the coherence of the ordinary biomatter from its own long scale quantum coherence.
The gene expression changes since the epigenetic control mechanisms involving for instance methylation and acetylation cease to function properly. The number of non-expressed genes increases. A chaotic behavior in the conformational degrees of freedom of DNA paired with dark DNA at its MB.
One can of course argue that there could exist an ageing gene. If cells would not age it would not take a long time for metabolic resources to deplete. However, the second law can generously take care of ageing.
Living systems are however able to fight against ageing. This is a mystery from the point of view of standard physics. One could argue that metabolic energy feed is enough but living systems are also critical and even quantum critical systems able to remain so: this is like a ball getting again and again at the top of the needle. How is this possible?
Here the zero energy ontology, which is behind TGD based quantum theory comes at rescue: "big" (ordinary) state function (BSFR) for subsystems changes the arrow of time and dissipation looks like self-organization and self-organized quantum criticality becomes possible. Generalized thermodynamics also allows metabolism as an extraction of even thermal energy from surroundings. Stress proteins could do this and be near physiological temperature and also act as heaters of DNA and proteins in cold shock and as heat engines driving molecular motors. Time reversal would happen also in the de-differentiation to stem cells.
Ageing would be basically heat death in this framework. The MBs of information molecules like DNA controlling them must be at much lower temperature than the physiological temperature otherwise they would not be information molecules. Physiological temperature would be near the maximal temperature - Hagedorn temperature of the string-like flux tubes of MB. The MBs however approach thermal equilibrium with the environment. Eventually heat death results and leads to BSFR (death followed life in reversed time direction) at the level of the entire organism.
The shortening of telomeres is also related to ageing. In TGD framework, the sticky ends associated with them would correspond to the decrease of the electric field strength along DNA. The opposite charges would be associated with sticky ends at the ends of chromosome. This possible in TGD framework.
The strength of the longitudinal electric field would correlate with level of consciousness for DNA just as the electric field along body axis correlates with the level of consciousness for humans and animals - this was discovered by Becker long time ago. When the electric field weakens, the level of consciousness is reduced. When the direction of the field changes consciousness is lost.
Ageing would involve weakening of this electric field, the energy density of DNA (plus its magnetic body) would be reduced, and the DNA string would become "sloppy" and start to behave randomly. This is part of the ageing.
We wrote an article about this with Reza Rastmanesh: see this .
For background see the article The based view about dark matter at the level of molecular biology written together with Reza Rastmanesh.
For a summary of earlier postings see Latest progress in TGD.