The G+C content of DNA is the ratio of guanine and cytosine to the total amount of nucleotides in the genome. This characteristic is widely used in taxonomic descriptions of prokaryotic microorganisms.

Traditionally, this value was obtained through laborious techniques such as thermal denaturation of genomic DNA and DNA separation by CsCl buoyant density. More recently, techniques such as HPLC separation or real-time PCR calculation have been used.

Currently, the value of the G+C mol% content is based on the genomic sequence of the strain.

Material needed

Genomic sequence of the microorganism.

If sequencing of the strain is needed, active culture or genomic DNA of the strain to be characterised is required.

More than 2 micrograms of genomic DNA at a concentration of 40 ng/µl suspended in ultrapure water or TE buffer, with A260/A280 values between 1,8 and 2, is needed.