molecular clock

noun

Medical Definition of molecular clock

: a measure of evolutionary change over time at the molecular level that is based on the theory that specific DNA sequences or the proteins they encode spontaneously mutate at constant rates and that is used chiefly for estimating how long ago two related organisms diverged from a common ancestor

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“Molecular clock.” Merriam-Webster.com Medical Dictionary, Merriam-Webster, https://www.merriam-webster.com/medical/molecular%20clock. Accessed 16 Jan. 2021.

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