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Updated: Jul 14, 2026

Metagenomic Analysis of Silage
Published on: January 13, 2017
Indexing strategies for rapid searches of short words in genome sequences
Christian Iseli1, Giovanna Ambrosini, Philipp Bucher
1Ludwig Institute for Cancer Research, Bâtiment Génopode, Université de Lausanne, Lausanne, Switzerland; Swiss Institute of Bioinformatics, Bátiment Génopode, Université de Lausanne, Lausanne, Switzerland. Christian. Iseli@lic.org
Abstract:
Searching for matches between large collections of short (14-30 nucleotides) words and sequence databases comprising full genomes or transcriptomes is a common task in biological sequence analysis. We investigated the performance of simple indexing strategies for handling such tasks and developed two programs, fetchGWI and tagger, that index either the database or the query set. Either strategy outperforms megablast for searches with more than 10,000 probes. FetchGWI is shown to be a versatile tool for rapidly searching multiple genomes, whose performance is limited in most cases by the speed of access to the filesystem. We have made publicly available a Web interface for searching the human, mouse, and several other genomes and transcriptomes with oligonucleotide queries.
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