External transcribed spacer (ETS) refers to a piece of non-functional

RNA Ribonucleic acid (RNA) is a polymeric molecule that is essential for most biological functions, either by performing the function itself (non-coding RNA) or by forming a template for the production of proteins (messenger RNA). RNA and deoxyrib ...

, closely related to the

internal transcribed spacer Internal transcribed spacer (ITS) is the spacer DNA situated between the small-subunit ribosomal RNA (rRNA) and large-subunit rRNA genes in the chromosome or the corresponding transcribed region in the polycistronic rRNA precursor transcript. ...

, which is situated outside structural ribosomal RNAs (rRNA) on a common precursor transcript. ETS sequences characteristic to an organism can be used to trace its

phylogeny A phylogenetic tree or phylogeny is a graphical representation which shows the evolutionary history between a set of species or Taxon, taxa during a specific time.Felsenstein J. (2004). ''Inferring Phylogenies'' Sinauer Associates: Sunderland, M ...

References

{{genetics-stub DNA Phylogenetics de:Spacer (Biologie)