What property of Taq polymerase made it essential for the development of PCR?

The critical property of Taq polymerase that made it essential for the development of the polymerase chain reaction (PCR) is its heat-stability. Taq polymerase is derived from the bacterium Thermus aquaticus, which thrives in high-temperature environments, such as hot springs. This heat-stability allows Taq polymerase to withstand the high temperatures used in PCR cycles without denaturing, which would typically deactivate most other DNA polymerases.

During PCR, the process involves denaturation, where the double-stranded DNA is heated to separate it into single strands. Following this, the temperature is lowered for annealing and extension phases. Taq polymerase can remain active during these temperature fluctuations, facilitating the synthesis of new DNA strands by extending from primers at elevated temperatures. This unique ability to function optimally at higher temperatures is what distinguishes Taq polymerase and makes it an indispensable enzyme in the PCR method, allowing for the amplification of DNA in a simple and efficient manner.