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Taq polymerase is a thermostable DNA polymerase I named after the thermophilic eubacterial microorganism Thermus aquaticus, from which it was originally isolated by Chien et al. in 1976. Its name is often abbreviated to Taq or Taq pol. It is frequently used in the polymerase chain reaction (PCR), a method for greatly amplifying the quantity of short segments of DNA. T. aquaticus is a bacterium that lives in hot springs and hydrothermal vents, and Taq polymerase was identified as an enzyme able to withstand the protein-denaturing conditions (high temperature) required during PCR. Therefore, it replaced the DNA polymerase from E. coli originally used in PCR. In the early 1980s, Kary Mullis was working at Cetus Corporation on the application of synthetic DNAs to biotechnology. He was familiar with the use of DNA oligonucleotides as probes for binding to target DNA strands, as well as their use as primers for DNA sequencing and cDNA synthesis. In 1983, he began using two primers, one to hybridize to each strand of a target DNA, and adding DNA polymerase to the reaction. This led to exponential DNA replication, greatly amplifying discrete segments of DNA between the primers. However, after each round of replication the mixture needs to be heated above 90 °C to denature the newly formed DNA, allowing the strands to separate and act as templates in the next round of amplification. This heating step also inactivates the DNA polymerase that was in use before the discovery of Taq polymerase, the Klenow fragment (sourced from E. coli). Taq polymerase is well-suited for this application because it is able to withstand the temperature of 95 °C which is required for DNA strand separation without denaturing. Use of the thermostable Taq enables running the PCR at high temperature (~60 °C and above), which facilitates high specificity of the primers and reduces the production of nonspecific products, such as primer dimer. Also, use of a thermostable polymerase eliminates the need to add new enzyme to each round of thermocycling. A single closed tube in a relatively simple machine can be used to carry out the entire process. Thus, the use of Taq polymerase was the key idea that made PCR applicable to a large variety of molecular biology problems concerning DNA analysis. Problems: Which of the following characteristics of Taq polymerase make it useful in the PCR process? A) It is heat stable and can withstand the heating step of PCR. B) It binds more readily than other polymerases to helicase C) It has regions that are complementary to the primers. D) It is exclusively moves from the 3' direction to the 5' direction. Which of the following statements about human reproduction is true? A) Mitosis in males is also known as spermatogenesis. B) Sperm and ova are zygotes. C) Oögenesis takes place in the ovaries of females. #NikolaysGeneticsLessons #biorad #biorad #PCR #realTimePcr #qpcr #GeneExpression #isoThermalPcr #genomics #amplification #bioRad #polymerase #pcrPolymerase #functionOfTaq #TaqPolymerase #characteristicsOfPcr #PfuPolymerase #Taq #PCRProcedure #pcrApplications #pcrSteps #pcrDefinition #pcrTemperatures #PCRTest #pcrProtocol #DNAAmplification #PCRAnimation #template #Primers #taqDNAPolymerase #PCRYoutube
