What did the Nobel laureates' foundational knowledge enable the tracking of at the most fundamental level?

Biology itself, specifically at the genetic level

The distinction between tracking the *output* of the clock (like sleep/activity measured by modern gadgets) and understanding the *cause* of the output is central to the Nobel achievement. The intellectual framework established by the laureates—the identification and mapping of genes such as *Period*, *Timeless*, *Clock*, and *Bmal1*—provided the ability to track the underlying biological machinery. This foundational knowledge allowed researchers to observe and decode the very genetic mechanisms that govern daily timing, moving beyond descriptive observation of rhythm to understanding the fundamental molecular basis that permits such tracking in the first place across nearly all life forms.