First of all I am a physicist, so I apologise for my non-existent understanding of basic biology. However, I have what I think is an interesting question and this seems like a good place to ask it...

I’ve recently been thinking whether there is a way to measure time using biological processes. In other words some system, a characteristic of which can be correlated to elapsed time. One example I can come up with is counting the number of divisions of a cell. I guess this can be done, but will most likely be highly inaccurate…

So this is my question: Do you know of any papers even tangentially related to the idea of a biological system that can be used as a clock?

Any ideas will be greatly appreciated!

  • $\begingroup$ I don't think circadian rhythms are accurate enough to be used as a clock. $\endgroup$
    – batboio
    Oct 1, 2019 at 8:06
  • $\begingroup$ What kind of time frame do you want to measure time on? If you want centuries / millenia / millions of years, you can look at the accumulated mutations in the noncoding sections of DNA; it's how we measure how long it's been since the last common ancestor of related species. $\endgroup$ Oct 2, 2019 at 14:52
  • $\begingroup$ Fascinating question, thanks for asking! Welcomg to Bio.SE! $\endgroup$
    – James
    Oct 2, 2019 at 14:54
  • $\begingroup$ @Orange_Striped_Gecko I was hoping for minutes (or even seconds). $\endgroup$
    – batboio
    Oct 3, 2019 at 4:35

1 Answer 1


There are lots of biological clocks, or clocks made of biological components. The circadian clock is an important, though complicated, example. There are excellent engineered clocks that form some of the neatest examples of systems / synthetic biology. See for example Elowitz & Leibler's "repressilator" (link, link). The basic idea in all of these is to have gene regulatory circuits with feedback that lead to oscillation of the gene expression dynamics. Books on systems biology, or Philip Nelson's Physical Models of Living Systems (aimed at physicists), are good places to read more.

  • $\begingroup$ Thanks! I will look into this. $\endgroup$
    – batboio
    Oct 1, 2019 at 8:22

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