Molecular clock

/məˈlɛkjələr klɑk/ noun

Definition

A technique that uses the rate of genetic mutations to estimate when two species diverged from a common ancestor. It assumes that mutations accumulate at a relatively constant rate over time.

Etymology

Coined in 1965 by biochemist Emile Zuckerkandl and chemist Linus Pauling, combining 'molecular' from Latin 'molecula' meaning 'small mass' and 'clock' from Middle Dutch 'klocke'. They discovered that protein differences between species correlated with their evolutionary divergence times.

Kelly Says

DNA is like a molecular historian that keeps track of evolutionary time - scientists can literally count genetic changes like tree rings to figure out when species split apart! The most amazing discovery was that humans and chimpanzees diverged only 6-7 million years ago, much more recently than anyone expected.

Related Words

Explore More Words

Get the Word Orb API

Complete word intelligence in one call. Free tier — 50 lookups/day.