License: Creative Commons Attribution 3.0 Unported license (CC BY 3.0)
When quoting this document, please refer to the following
DOI: 10.4230/LIPIcs.WABI.2019.16
URN: urn:nbn:de:0030-drops-110461
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Tiskin, Alexander

Bounded-Length Smith-Waterman Alignment

LIPIcs-WABI-2019-16.pdf (0.4 MB)


Given a fixed alignment scoring scheme, the bounded length (respectively, bounded total length) Smith-Waterman alignment problem on a pair of strings of lengths m, n, asks for the maximum alignment score across all substring pairs, such that the first substring's length (respectively, the sum of the two substrings' lengths) is above the given threshold w. The latter problem was introduced by Arslan and Egecioglu under the name "local alignment with length threshold". They proposed a dynamic programming algorithm solving the problem in time O(mn^2), and also an approximation algorithm running in time O(rmn), where r is a parameter controlling the accuracy of approximation. We show that both these problems can be solved exactly in time O(mn), assuming a rational scoring scheme; furthermore, this solution can be used to obtain an exact algorithm for the normalised bounded total length Smith - Waterman alignment problem, running in time O(mn log n). Our algorithms rely on the techniques of fast window-substring alignment and implicit unit-Monge matrix searching, developed previously by the author and others.

BibTeX - Entry

  author =	{Alexander Tiskin},
  title =	{{Bounded-Length Smith-Waterman Alignment}},
  booktitle =	{19th International Workshop on Algorithms in Bioinformatics (WABI 2019)},
  pages =	{16:1--16:12},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-123-8},
  ISSN =	{1868-8969},
  year =	{2019},
  volume =	{143},
  editor =	{Katharina T. Huber and Dan Gusfield},
  publisher =	{Schloss Dagstuhl--Leibniz-Zentrum fuer Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{},
  URN =		{urn:nbn:de:0030-drops-110461},
  doi =		{10.4230/LIPIcs.WABI.2019.16},
  annote =	{Keywords: sequence alignment, local alignment, Smith, Waterman alignment, matrix searching}

Keywords: sequence alignment, local alignment, Smith, Waterman alignment, matrix searching
Collection: 19th International Workshop on Algorithms in Bioinformatics (WABI 2019)
Issue Date: 2019
Date of publication: 03.09.2019

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