molecular clock(redirected from Gene clock)
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Related to Gene clock: Molecular clock hypothesis
1. An assumed approximately constant rate of change over evolutionary time in the nucleotide sequences of DNA molecules and the amino acid sequences of protein molecules.
2. A technique based on this assumption, in which the amount of time since two species or other taxa diverged from a common ancestor is estimated by measuring the number of differences between certain gene or protein sequences of the taxa.
The American Heritage® Medical Dictionary Copyright © 2007, 2004 by Houghton Mifflin Company. Published by Houghton Mifflin Company. All rights reserved.