Organization of the eukaryotic nuclear ribosomal DNA tandem repeats.
External transcribed spacer (ETS) refers to a piece of non-functionalRNA, closely related to theinternal transcribed spacer, which is situated outside structural ribosomal RNAs (rRNA) on a common precursor transcript.[1] ETS sequences characteristic to an organism can be used to trace itsphylogeny.[2]
^Schibler, U.; Wyler, T.; Hagenbuchle, O. (1975). "Changes in size and secondary structure of the ribosomal transcription unit during vertebrate evolution".Journal of Molecular Biology.94 (3):503–17.doi:10.1016/0022-2836(75)90217-X.PMID809590.
^Baldwin, B. G.; Markos, S. (1998). "Phylogenetic utility of the external transcribed spacer (ETS) of 18S-26S rDNA: Congruence of ETS and ITS trees of Calycadenia (Compositae)".Molecular Phylogenetics and Evolution.10 (3):449–63.doi:10.1006/mpev.1998.0545.PMID10051397.
