DNA spiking, also known as custom spiking, is the differing ratio of bases at a single degenerate position when synthesizing oligonucleotides. DNA spiking is a unequal proportions of bases at a given position (for example, 10%

Adenine Adenine (, ) (nucleoside#List of nucleosides and corresponding nucleobases, symbol A or Ade) is a purine nucleotide base that is found in DNA, RNA, and Adenosine triphosphate, ATP. Usually a white crystalline subtance. The shape of adenine is ...

, 75%

Guanine Guanine () (symbol G or Gua) is one of the four main nucleotide bases found in the nucleic acids DNA and RNA, the others being adenine, cytosine, and thymine ( uracil in RNA). In DNA, guanine is paired with cytosine. The guanine nucleoside ...

, 5%

Cytosine Cytosine () (symbol C or Cyt) is one of the four nucleotide bases found in DNA and RNA, along with adenine, guanine, and thymine ( uracil in RNA). It is a pyrimidine derivative, with a heterocyclic aromatic ring and two substituents attac ...

& 10%

Thymine Thymine () (symbol T or Thy) is one of the four nucleotide bases in the nucleic acid of DNA that are represented by the letters G–C–A–T. The others are adenine, guanine, and cytosine. Thymine is also known as 5-methyluracil, a pyrimidine ...

). As an example, with the

degenerate code Genetic code is a set of rules used by living cells to translate information encoded within genetic material (DNA or RNA sequences of nucleotide triplets or codons) into proteins. Translation is accomplished by the ribosome, which links proteinog ...

R = A + G, 50% of the time that R position is adenine and the other 50% of the time it is guanine. However, with DNA Spiking, the R position could be adenine 70% of the time and guanine 30% of the time. The proportions do not need to be 70:30, the ratios can be anything else such as 12:82 and 64:36. DNA spiking can also refer to a spike control in PCR, which is when DNA is added to a sample that will provide some signal (e.g. a

plasmid A plasmid is a small, extrachromosomal DNA molecule within a cell that is physically separated from chromosomal DNA and can replicate independently. They are most commonly found as small circular, double-stranded DNA molecules in bacteria and ...

or some synthetic DNA with a specific known sequence) to a reaction, and seeing if the reaction will amplify. This method is used to discover if the PCR method is working correctly, as in a PCR machine it may not amplify DNA properly, so by adding spiked DNA it can be observed how much DNA is produced. This is then compared to the amount of DNA that would be theoretically predicted if the machine was working properly so that any malfunctions can be discovered.

References

{{reflist DNA Biochemistry

See also

References