master mix (PCR)
{{Short description|Mixture used in molecular biology}}
{{Use British English|date=April 2020}}
A master mix is a mixture containing precursors and enzymes used as an ingredient in polymerase chain reaction techniques in molecular biology. Such mixtures contain a mixture dNTPs (required as a substrate for the building of new DNA strands), MgCl2, Taq polymerase (an enzyme required to building new DNA strands), a pH buffer and come mixed in nuclease-free water.{{cite web |title=PCR Master Mix |url=https://www.sigmaaldrich.com/life-science/molecular-biology/pcr/pcr-master-mix.html |website=Sigma-Aldrich |publisher=Merck |language=en}}{{cite web |title=GoTaq® G2 Master Mixes {{!}} PCR Master Mix |url=https://www.promega.co.uk/products/pcr/taq-polymerase/pcr-master-mix/?catNum=M7822 |website=www.promega.com}}{{cite web |title=PCR Master Mix {{!}} Bio-Rad |url=https://www.bio-rad.com/featured/en/pcr-master-mix.html |website=www.bio-rad.com |publisher=Bio Rad}}{{cite web |title=PCR Master Mixes {{!}} Chai |url=https://www.chaibio.com/pcr-master-mix |website=www.chaibio.com |publisher=Chai}}
Master mixes for real-time PCR include a fluorescent compound (frequently SYBR green), and the choice of mix also influence test sensitivity and consistency.{{cite journal |last1=Yang |first1=Jianxin |last2=Kemps-Mols |first2=Berit |last3=Spruyt-Gerritse |first3=Marijke |last4=Anholts |first4=Jacqueline |last5=Claas |first5=Frans |last6=Eikmans |first6=Michael |title=The source of SYBR green master mix determines outcome of nucleic acid amplification reactions |journal=BMC Research Notes |date=4 June 2016 |volume=9 |issue=1 |page=292 |doi=10.1186/s13104-016-2093-4|pmid=27259280 |doi-access=free |pmc=4893258 }}
Differences in the choice of master mixes can sometimes explain difference in experimental results, a particular case being the measurement of telomere length.{{cite journal |last1=Jiménez |first1=Karen M. |last2=Forero |first2=Diego A. |title=Effect of master mixes on the measurement of telomere length by qPCR |journal=Molecular Biology Reports |date=5 April 2018 |volume=45 |issue=4 |pages=633–638 |doi=10.1007/s11033-018-4175-y|pmid=29623565 |s2cid=254833450 }}{{cite journal |last1=Lin |first1=Jue |last2=Smith |first2=Dana L. |last3=Esteves |first3=Kyle |last4=Drury |first4=Stacy |title=Telomere length measurement by qPCR – Summary of critical factors and recommendations for assay design |journal=Psychoneuroendocrinology |date=January 2019 |volume=99 |pages=271–278 |doi=10.1016/j.psyneuen.2018.10.005|pmid=30343983 |pmc=6363640 }}