Evolution of Molecular Clock Concepts
Molecular clocks played a significant role in the search for evidence of biological evolution over the past seventy-five years. Driven by biotechnological advances, the integration of molecules with morphology reflects the shift from Darwinism to the Modern Synthesis theory of evolution.
Early formulations of the molecular-clock concept assumed that biological molecules—DNA, RNA, and proteins—accumulated sequence changes at consistant rates. These changes were envisioned to as chronological signatures within a lineage, similar to growth rings in a tree trunk. By tracing the order and magnitude of these changes, researchers expected to reconstruct the evolutionary history of each species.
