The ambition to unlock the key to unravel the aging process is a common pursuit among scientists.

Tom Kirkwood’s ambition, as a mathematician delving into medical research, is centered on unlocking the key to addressing the aging process in humans.

After two decades of researching blood disorders, Kirkwood shifted his focus to the aging of observed cells in laboratory experiments. This interest stemmed from a fortuitous meeting with molecular biologist Robin Holliday, who sought his assistance in modeling errors that could occur during DNA replication across cell generations. Perhaps, the key to explaining our aging lies in this realm.

Although aging is not directly related to his blood research, Kirkwood found intrigue in this subject. During his leisure moments, he explored this field and grasped the ideas put forth by August Weismann.

The question “Why do we age?” is a puzzle that many scientists are working hard to solve. As Kirkwood’s thoughts crystallized, he developed a theory of aging based on the distinction between immortal stem cells and vital somatic cells. He published this theory in the paper “The Somatic Disposal Theory of Aging” in the journal Nature in 1977.

In essence, Kirkwood’s theory can be summarized as follows: for every living organism, the most critical biological task is to exist long enough to reproduce and nurture offspring. Safeguarding stem cells to prevent errors during division is paramount, with somatic cells serving just enough to generate the next generation.

According to Kirkwood, only stem cells are immortal, and the body ages as a result of insufficient investment in maintenance. This is the outcome of natural selection, focusing on the survival of individual organisms within a species rather than the entire species.

I first met Tom Kirkwood in the early 1990s while producing a documentary on aging for the BBC. In a later meeting, he shared more information about the somatic disposal theory and how he arrived at these insights.

Note: This article utilizes information, images from Armstrong