The formal version of the Information Theory of Aging was first formulated in 2014 while I was in Fiji and was later described in my book Lifespan: Why We Ageโand Why We Donโt Have To Die.
The idea started in the 1990s, when I was working in the laboratory of Leonard Guarente at MIT, one of the pioneers of modern aging research.
At a time when many scientists viewed aging as an inevitable process of wear and tear, Lennyโs laboratory was helping reveal that lifespan could be regulated by specific genes and cellular pathways.
The groundbreaking work on the SIR genes in yeast (which stands for silent information regulator) established a connection between chromatin structure, gene regulation, and longevity that continues to influence the field today.
As part of that research team, I became interested in a simple but profound paradox. If most cells maintain essentially the same DNA sequence throughout life, why do they progressively lose function? Why do young cells know how to repair themselves and maintain their identity, while old cells gradually lose those abilities?
Even in yeast, it was clear that aging cells were losing control of gene expression despite retaining much of their genetic information. These observations led me to wonder whether aging might involve more than the accumulation of mutations and molecular damage. Perhaps cells were losing access to some of the information required to read the genome correctly. This was the theoryโs origins in 1995-1999
Over the following years, this idea continued to evolve. In my laboratory at Harvard Medical School, Philipp Oberdoerffer led a series of experiments examining how chromatin regulators respond to DNA damage. In a landmark study (Oberdoerffer et al., Cell, 2008), we found that proteins involved in maintaining chromatin structure relocate across the genome to help repair DNA breaks. While this response protects the genome, it can also alter patterns of gene regulation. We proposed that repeated cycles of DNA repair might gradually disrupt epigenetic organization over time, generating biological noise that accumulates throughout life. This became known as the Relocalization of Chromatin Modifiers hypothesis and provided an important conceptual foundation for later work.
For many years, however, these ideas remained largely speculative. Then a series of discoveries began to provide support.
One came from Steve Horvathโs development of epigenetic clocks (Horvath, Genome Biology, 2013). By measuring DNA methylation patterns, Horvath showed that biological age could be predicted with remarkable accuracy across many tissues. For the first time, aging appeared to leave a measurable signature on the epigenome itself.
Another important advance came from the laboratory of Juan Carlos Izpisua Belmonte. In 2016, his group demonstrated that transient expression of the Yamanaka factors could reverse multiple features of aging and extend lifespan in a mouse model of progeria (Ocampo et al., Cell, 2016). The work suggested that aspects of biological age might be reversible without permanently erasing cellular identity.
Around 2010, my laboratory began designing experiments to directly test whether disruption of epigenetic information could itself drive aging in a mammal, not just a yeast cellโฆ