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Documents authored by Lonardi, Stefano


Document
ThIEF: Finding Genome-wide Trajectories of Epigenetics Marks

Authors: Anton Polishko, Md. Abid Hasan, Weihua Pan, Evelien M. Bunnik, Karine Le Roch, and Stefano Lonardi

Published in: LIPIcs, Volume 88, 17th International Workshop on Algorithms in Bioinformatics (WABI 2017)


Abstract
We address the problem of comparing multiple genome-wide maps representing nucleosome positions or specific histone marks. These maps can originate from the comparative analysis of ChIP-Seq/MNase-Seq/FAIRE-Seq data for different cell types/tissues or multiple time points. The input to the problem is a set of maps, each of which is a list of genomics locations for nucleosomes or histone marks. The output is an alignment of nucleosomes/histone marks across time points (that we call trajectories), allowing small movements and gaps in some of the maps. We present a tool called ThIEF (TrackIng of Epigenetic Features) that can efficiently compute these trajectories. ThIEF comes into two "flavors": ThIEF:Iterative finds the trajectories progressively using bipartite matching, while ThIEF:LP solves a k-partite matching problem on a hyper graph using linear programming. ThIEF:LP is guaranteed to find the optimal solution, but it is slower than ThIEF:Iterative. We demonstrate the utility of ThIEF by providing an example of applications on the analysis of temporal nucleosome maps for the human malaria parasite. As a surprisingly remarkable result, we show that the output of ThIEF can be used to produce a supervised classifier that can accurately predict the position of stable nucleosomes (i.e., nucleosomes present in all time points) and unstable nucleosomes (i.e., present in at most half of the time points) from the primary DNA sequence. To the best of our knowledge, this is the first result on the prediction of the dynamics of nucleosomes solely based on their DNA binding preference. Software is available at https://github.com/ucrbioinfo/ThIEF.

Cite as

Anton Polishko, Md. Abid Hasan, Weihua Pan, Evelien M. Bunnik, Karine Le Roch, and Stefano Lonardi. ThIEF: Finding Genome-wide Trajectories of Epigenetics Marks. In 17th International Workshop on Algorithms in Bioinformatics (WABI 2017). Leibniz International Proceedings in Informatics (LIPIcs), Volume 88, pp. 19:1-19:16, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2017)


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@InProceedings{polishko_et_al:LIPIcs.WABI.2017.19,
  author =	{Polishko, Anton and Hasan, Md. Abid and Pan, Weihua and Bunnik, Evelien M. and Le Roch, Karine and Lonardi, Stefano},
  title =	{{ThIEF: Finding Genome-wide Trajectories of Epigenetics Marks}},
  booktitle =	{17th International Workshop on Algorithms in Bioinformatics (WABI 2017)},
  pages =	{19:1--19:16},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-050-7},
  ISSN =	{1868-8969},
  year =	{2017},
  volume =	{88},
  editor =	{Schwartz, Russell and Reinert, Knut},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.WABI.2017.19},
  URN =		{urn:nbn:de:0030-drops-76375},
  doi =		{10.4230/LIPIcs.WABI.2017.19},
  annote =	{Keywords: Nucleosomes, Histone Marks, Histone Tail Modifications, Epigenetics, Genomics}
}
Document
Efficient and Accurate Detection of Topologically Associating Domains from Contact Maps

Authors: Abbas Roayaei Ardakany and Stefano Lonardi

Published in: LIPIcs, Volume 88, 17th International Workshop on Algorithms in Bioinformatics (WABI 2017)


Abstract
Continuous improvements to high-throughput conformation capture (Hi-C) are revealing richerinformation about the spatial organization of the chromatin and its role in cellular functions.Several studies have confirmed the existence of structural features of the genome 3D organiza-tion that are stable across cell types and conserved across species, calledtopological associatingdomains(TADs). The detection of TADs has become a critical step in the analysis of Hi-C data,e.g., to identify enhancer-promoter associations. Here we presentEast, a novel TAD identifi-cation algorithm based on fast 2D convolution of Haar-like features, that is as accurate as thestate-of-the-art method based on the directionality index, but 75-80x faster.Eastis availablein the public domain at https://github.com/ucrbioinfo/EAST.

Cite as

Abbas Roayaei Ardakany and Stefano Lonardi. Efficient and Accurate Detection of Topologically Associating Domains from Contact Maps. In 17th International Workshop on Algorithms in Bioinformatics (WABI 2017). Leibniz International Proceedings in Informatics (LIPIcs), Volume 88, pp. 22:1-22:11, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2017)


Copy BibTex To Clipboard

@InProceedings{roayaeiardakany_et_al:LIPIcs.WABI.2017.22,
  author =	{Roayaei Ardakany, Abbas and Lonardi, Stefano},
  title =	{{Efficient and Accurate Detection of Topologically Associating Domains from Contact Maps}},
  booktitle =	{17th International Workshop on Algorithms in Bioinformatics (WABI 2017)},
  pages =	{22:1--22:11},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-050-7},
  ISSN =	{1868-8969},
  year =	{2017},
  volume =	{88},
  editor =	{Schwartz, Russell and Reinert, Knut},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.WABI.2017.22},
  URN =		{urn:nbn:de:0030-drops-76446},
  doi =		{10.4230/LIPIcs.WABI.2017.22},
  annote =	{Keywords: Chromatin, TADs, 3D genome, Hi-C, contact maps}
}
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