Bengtsson-Palme, J., Ryberg, M., Hartmann, M., Branco, S., Wang, Z., Godhe, A., De Wit, P., Sánchez-García, M., Ebersberger, I., de Sousa, F., Amend, A., Jumpponen, A., Unterseher, M., Kristiansson, E., Abarenkov, K., Bertrand, Y.J.K., Sanli, K., Eriksson, K.M., Vik, U., Veldre, V. and Nilsson, R.H.

Methods Ecol Evol, 4: 914-919. 2013

Improved software detection and extraction of ITS1 and ITS2 from ribosomal ITS sequences of fungi and other eukaryotes for analysis of environmental sequencing data.

Fungal HMMs were computed for a 45-base-pair region of the immediate 3′ end of SSU, the 5′ and 3′ ends of 5.8S, and the 5′ end of LSU [...] The SSU is extracted as everything from the 5′ end of the query sequence to the 3′ end of SSU as indicated by the HMM match; the ITS1 is extracted 1 bp downstream from the end of SSU and 1 bp upstream of the start of 5.8S; and so on. [...] we evaluated the proportion of false positives by generating one million random sequences of 550 bp [...] Zero false-positive ‘ITS’ sequences were detected among the random sequences [...] The extractor cannot identify sequences of SSU, 5.8S or LSU shorter than c. 20 bp (25 bp for consistent performance)