molecular clock

American  

noun

1. the changes in the amino acid sequences of proteins that take place during evolution and speciation, and from which the dates of branchings of taxonomic groups can be deduced.

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Example Sentences

Scientists have used molecular clock estimates, which track the accumulation of genetic mutations over time, to suggest that sponges first evolved around 700 million years ago.

From Science Daily • Apr. 15, 2026

The leading theory is that these insects have an internal molecular clock synced to the seasonal flow of fluid, or xylem, that passes through a tree’s roots each spring, which cicadas sip on as food.

From National Geographic • Sep. 5, 2023

Gallone cautions, for example, that the molecular clock date is a rough estimate.

From Science Magazine • Apr. 26, 2023

Explain how such a molecular clock could be refined to infer time for the evolution of prokaryotes.

From Textbooks • Jun. 9, 2022

Recent studies in animals and people show that almost every cell in our bodies contains a version of a molecular clock that coordinates with a broader, full-body timing system to direct most biological operations.

From New York Times • Jan. 19, 2022