PCR

PCR, polymerase chain reation, is used to create replications of DNA in the lab.  Temperatures of a bath are raised and cooled to ge the double strands to separate, primers to be inserted and tac polymerase will extend the stand.  The process is left with short stands of target sequences which have been replicated as they were defined by primers.  This started as a labor intensive process which required hours of manual labor and a large quanitites of enzymes until a bath was invented which allowed for the thermoregulation of the temperature.