RT Journal Article SR Electronic T1 CRAST Leads to Homologous-ncRNA Search in Genomic Scale JF bioRxiv FD Cold Spring Harbor Laboratory SP 127738 DO 10.1101/127738 A1 Masaki Tagashira YR 2017 UL http://biorxiv.org/content/early/2017/04/29/127738.abstract AB Motivation Non-coding RNAs (ncRNAs) play important roles in various biological processes. In past, homologousncRNA search in genomic scale (e.g., search all house mouse ncRNAs for several human ones) is difficult since explicit consideration of secondary structure in alignment leads to impractical complexity on both of time and space.Results In this study, building the program CRAST (Context RNA Alignment Search Tool, available at “https://github.com/heartsh/crast” including the used validation/test set), we developed the CRAST algorithm, a “seed-and-extend” alignment one based on adaptive seed and RNA secondary structure context (motif probabilities) as in Fig. 1. The algorithm is O(n: a sum of lengths of target sequences) on time through help of adaptive seed, implicitly considering both of sequence and secondary structure; it provides computation time comparable with other BLAST-like tools, significantly reduced from any variant of the Sankoff algorithm for alignment with the explicit consideration. It detects homologs as many as other BLAST-like tools and the lowest number of non-homologous ncRNAs.