PT - JOURNAL ARTICLE AU - Daniel G.C. Treen AU - Trent R. Northen AU - Benjamin P. Bowen TI - SIMILE enables alignment of fragmentation mass spectra with statistical significance AID - 10.1101/2021.02.24.432767 DP - 2021 Jan 01 TA - bioRxiv PG - 2021.02.24.432767 4099 - http://biorxiv.org/content/early/2021/02/25/2021.02.24.432767.short 4100 - http://biorxiv.org/content/early/2021/02/25/2021.02.24.432767.full AB - Interrelating compounds according to their aligned fragmentation spectra is central to tandem mass spectrometry-based metabolomics. However, current alignment algorithms do not provide statistical significance and compounds that have multiple delocalized structural differences often fail to have their fragment ions aligned. Significant Interrelation of MS/MS Ions via Laplacian Embedding (SIMILE) is a new tool inspired by protein sequence alignment for aligning fragmentation spectra with statistical significance and allowance for multiple chemical differences. We found SIMILE yields 550% more pairs of structurally similar compounds than commonly used cosine-based scoring algorithms, and anticipate SIMILE will fill an important role by also providing p-values for fragmentation spectra alignments to explore structural relationships between compounds.Competing Interest StatementThe authors have declared no competing interest.