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DNA Polymerase Selection Chart

The following table lists properties that should be considered when choosing a polymerase. The degree of activity in your assay may not reflect the values of measurements of these properties because they are dependent on specific substrate, reaction conditions, and method of analysis.

DNA Polymerase Error Rate (fidelity) 3′-5′ Exonuclease 5′-3′ Exonuclease (5′ flap endo.) Strand Displacementh Reverse Transcriptaseh Resulting 3′ Ends RNA Primer Extension Nick Extension dU Tolerance Extension Temperature Max PCR Product
Thermophilic DNA Polymerases for PCR
Q5® High-Fidelity DNA Polymerases 5.3x10-7 (280X Taq) a ++++ - + - Blunt No No No 72°C 20 kb simple, 10 kb complexk
Q5®-XT Hot Start High-Fidelity 2X Master Mix 30 kb simple, 20 kb complexk
Q5U® Hot Start High-Fidelity DNA Polymerase 5.3x10-7 (280X Taq) a ++++ - + - Blunt No No Yes 72°C 20 kb simple, 10 kb complexk
Phusion™ High-Fidelity DNA Polymerases* 3.9x10-6 (39Xa-50Xb Taq) ++++ - + - Blunt No No No 72°C 20 kb simple, 10 kb complexk
OneTaq® DNA Polymerases (2X Taq) ++ Yes -i + 3' dA/Blunt No Yes Yes 68°C 6 kb
LongAmp® Polymerases (2X Taq) ++ Yes -i +  3' dA/Blunt No Yes Yes 68°C 30 kb
Taq Polymerases 1.5x10-4 (1X)a - Yes -i +++ 3' dA No Yes Yes 68°C 5 kb
Hemo KlenTaq nd - - ++++ + 3' dA No No Yes 68°C 2 kb
Epimark® Hot Start Taq DNA Polymerase nd - Yes -i + 3' dA No Yes Yes 68°C 5 kb
Vent® DNA Polymerase nd ++ - +++ - Blunt No Yes No 72°C 6 kb
Vent® (exo–) DNA Polymerase nd - - +++ - 3' dA No Yes No 72°C 6 kb
Deep Vent® DNA Polymerase 4x10-6 (44X Taq)a +++ - ++ - Blunt No Yes No 72°C 6 kb
Deep Vent® (exo–) DNA Polymerase 5x10-4 (0.3X Taq)a - - +++ - 3' dA/Blunt No Yes No 72°C 6 kb
DNA Polymerases for Isothermal Amplification Reactions
Bst DNA Polymerase, Full Length nd - Yes -i ++ 3' dA Yes Yes Yes 65°C  
Bst DNA Polymerase, Large Fragment nd - - +++ +++ 3' dA Yes Yes Yes 65°C  
Bst-XT WarmStart DNA Polymerase 5.3x10-5 c - - ++++ ++++ 3' dA Yes Yes Yes 50-70°C  
Bst 2.0® DNA Polymerase 6.2x10-5 d - - ++++ ++++ 3' dA Yes Yes Yes 60-70°C  
Bst 3.0® DNA Polymerase 7x10-5 d - - +++ ++++ 3' dA Yes Yes Yes 55-72°C  
Bsu DNA Polymerase, Large Fragment nd - - +++ ++ 3' dA Yes Yes Yes 37°C  
phi29 DNA Polymerase 5.3x10-5 c ++++ - ++++ - Blunt Yes Yesj Yes 30°C  
phi29-XT DNA Polymerase 2.6x10-5 c ++++ - ++++ - Blunt Yes Yesj Yes 42°C  
DNA Polymerases for DNA Manipulation
T4 DNA Polymerase <1x10-6 e ++++ - - - Blunt Yes No Yes 37°C  
T7 DNA Polymerase (unmodified) 1.5x10-5 f ++++ - - - Blunt Yes No Yes 37°C  
DNA Polymerase I (E. coli) 9x10-6 f ++ Yes -i +++ Blunt Yes Yes Yes 37°C  
DNA Polymerase I, Large (Klenow) Fragment 1.8x10-5 g ++ - ++ +++ Blunt Yes No Yes 37°C  
Klenow Fragment (3′→5′ exo-) 1x10-4 g - - +++ +++ 3' dA Yes No Yes 37°C  
Therminator™ DNA Polymerase nd - - ++ ++ 3' dA Yes No Yes 72°C  
Sulfolobus DNA Polymerase IV nd - - + ++++ 3' dA Yes No Yes 55°C  
Terminal Transferase nd - - - - 3' dN(x) nd No Yes 37°C  

+, ++, +++, ++++ Presence and relative degree of activity

- No observed activity

nd Not determined



Deep Vent® and Therminator™ are trademarks of New England Biolabs, Inc.
Q5®, Q5U®, LongAmp®, OneTaq®, Vent®, Deep Vent®, EpiMark®, Bst 2.0®, and Bst 3.0® are registered trademarks of New England Biolabs, Inc.

*Notice to Customers:
Phusion™ DNA Polymerase was developed by Finnzymes Oy, now a part of Thermo Fisher Scientific.
PHUSION™ and THERMO SCIENTIFIC™ are trademarks and property of Thermo Fisher Scientific.


References and Notes:

  1. Potapov, V., & Ong, J. L. (2017). Examining Sources of Error in PCR by Single_Molecule Sequencing. PloS one, 12(1), e0169774. doi: 10.1371/journal.pone.0169774 PMID: 28060945
  2. as reported my Finnzymes/Thermo Scientific.
  3. Unpublished results determined by the method in Betancourt-Anzola, L., et. al. (2025). NAR, 53(21). doi: 10.1093/nar/gkaf1143. PMID: 41273172.
  4. Potapov, V., Fu, X., Dai, N., Corrêa, I.R., Tanner, N.A., Ong, J.L. (2018) Base modifications affecting RNA polymerase and reverse transcriptase fidelity. Nucleic Acids Research, 46 (11), 5753–5763.doi: 10.1093/nar/gky341 PMID: 29750267.
  5. Kunkel, T.A., Loeb, L.A. and Goodman, M.F. (1984) J. Biol. Chem., 259, 1539–1545 PMID: 6229537.
  6. Mattila, P., Korpela, J., Tenkanen, T. and Pitkanen, K. (1991) Nucleic Acids Res., 19, 4967–4973. PMID: 1923765.
  7. Bebenek, K., Joyce, C.M., Fitzgerald, M.P. and Kunkel, T.A. (1990) J. Biol. Chem., 265, 13878–13887. PMID: 2199444.
  8. Assessing the reverse transcriptase and strand displacement activities of DNA polymerases via quantitative capillary electrophoresis.
  9. The displaced strand is digested by 5' flap endonuclease (5'-3' exonuclease) activity. See this FAQ for more detail.
  10. Phi29 is not efficient at initiating from a nick. We recommend Bsu or E. coli DNA Polymerase I for applications needing this activity.
  11. Simple templates include plasmid, viral, and E. coli genomic DNA. Complex templates include plant, human, and other mammalian genomic DNA and cDNA.