View source for Aging in Single-celled Organisms: from Bacteria to the Whole Tree of Life/MartinPicard

{{Attendee note
|Post-meeting summary=Experimental models to study cellular aging vary dramatically.

We clearly need a consensus definition of aging, or more specific concepts. Is aging the loss of specific functions, the loss in the ability to divide, "senescence" (which itself does not have a consensus definition), the movement towards mortality, or the accumulation of "information" over time? Can there be a single definition of aging across the tree of life - from single cells to complex multicellular organisms like mammals?

If the definition is a functional one - aging is the loss in the ability to perform X function, then aging needs to be contextualized. Organisms at different scales (prokaryotes vs birds vs humans) have dramatically different "purpose" in the living world, and they carry out very different functions. Is there one type of aging that unites them all? Or qualitatively different forms of aging, or aging processes?

An interdependent challenge with the previous one is the issue of measurement. What are good measures of aging - again it depends on how it is defined. 

If aging is defined as ''something'' that tells us how close to death an organism is to end of life (i.e,, mortality) or to loss of function, then it implies that aging biomarkers need to be developed prospectively. In other words, the aging marker need to predict some future behavior. One example is the DNA methylation or epigenetic clocks.
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