Internal transcribed spacer

ITS1 corresponds to the ITS in bacteria and archaea, while ITS2 originated as an insertion that interrupted the ancestral 23S rRNA gene.

[6] Sequence comparison of the eukaryotic ITS regions is widely used in taxonomy and molecular phylogeny because of several favorable properties:[7] For example, ITS markers have proven especially useful for elucidating phylogenetic relationships among the following taxa.

Regardless of the scope of conservation, structure-assisted comparison can provide higher resolution and robustness.

In addition to the universal ITS1+ITS4 primers[30][31] used by many labs, several taxon-specific primers have been described that allow selective amplification of fungal sequences (e.g., see Gardes & Bruns 1993 paper describing amplification of basidiomycete ITS sequences from mycorrhiza samples).

[32] Despite shotgun sequencing methods becoming increasingly utilized in microbial sequencing, the low biomass of fungi in clinical samples make the ITS region amplification an area of ongoing research.

Organization of the eukaryotic nuclear ribosomal DNA tandem repeats