Most cell types turn over on timescales of days to months. “Depletion” of any of these cell types cannot be a root cause of aging; either their production rate has decreased or their removal rate has increased.
In order for that to be a cause, those cell types would have to produce each other (and a decrease across the board, would lead to a decrease in the production rate).
Correct. However, even in that case, the overall level would still reach a steady-state on a timescale much faster than aging itself. More generally, feedback loops equilibrate on roughly the timescale of their slowest component. So, even if there’s a feedback loop in the mix, it still can’t be a root cause of aging unless one of the components is out-of-equilibrium on a timescale comparable to aging (i.e. decades or longer).
The root cause of aging is programmed aging. Bowhead Whales (mammals, genetics remarkably similar to a cow) live 230 years, Greenland Sharks live 430, arctic quahogs live over 500, various wacky plants live as long as religious memes.
In order for that to be a cause, those cell types would have to produce each other (and a decrease across the board, would lead to a decrease in the production rate).
Correct. However, even in that case, the overall level would still reach a steady-state on a timescale much faster than aging itself. More generally, feedback loops equilibrate on roughly the timescale of their slowest component. So, even if there’s a feedback loop in the mix, it still can’t be a root cause of aging unless one of the components is out-of-equilibrium on a timescale comparable to aging (i.e. decades or longer).
The root cause of aging is programmed aging. Bowhead Whales (mammals, genetics remarkably similar to a cow) live 230 years, Greenland Sharks live 430, arctic quahogs live over 500, various wacky plants live as long as religious memes.
Then I’d very much like to know what the program is, what its variables are, and in particular how the program state is stored.
“The root cause of aging is biology.”