33 research outputs found

    Periodic pattern detection in sparse boolean sequences

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    <p>Abstract</p> <p>Background</p> <p>The specific position of functionally related genes along the DNA has been shown to reflect the interplay between chromosome structure and genetic regulation. By investigating the statistical properties of the distances separating such genes, several studies have highlighted various periodic trends. In many cases, however, groups built up from co-functional or co-regulated genes are small and contain wrong information (data contamination) so that the statistics is poorly exploitable. In addition, gene positions are not expected to satisfy a perfectly ordered pattern along the DNA. Within this scope, we present an algorithm that aims to highlight periodic patterns in sparse boolean sequences, i.e. sequences of the type 010011011010... where the ratio of the number of 1's (denoting here the transcription start of a gene) to 0's is small.</p> <p>Results</p> <p>The algorithm is particularly robust with respect to strong signal distortions such as the addition of 1's at arbitrary positions (contaminated data), the deletion of existing 1's in the sequence (missing data) and the presence of disorder in the position of the 1's (noise). This robustness property stems from an appropriate exploitation of the remarkable alignment properties of periodic points in solenoidal coordinates.</p> <p>Conclusions</p> <p>The efficiency of the algorithm is demonstrated in situations where standard Fourier-based spectral methods are poorly adapted. We also show how the proposed framework allows to identify the 1's that participate in the periodic trends, i.e. how the framework allows to allocate a <it>positional score </it>to genes, in the same spirit of the sequence score. The software is available for public use at <url>http://www.issb.genopole.fr/MEGA/Softwares/iSSB_SolenoidalApplication.zip</url>.</p

    A New Approach to Design an Interactive System for Molecular Analysis

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    International audienceThe rapid evolution of molecule's imaging and observation's techniques has caused a growing interest in studying molecular structures. Naturally, scientists have turned to simulation and 3D modeling in order to better understand biological phenomena. Thus, several 3D modeling systems have emerged. Some of these systems are dedicated to 3D visualization, and others are interested in 3D handling. However, we observed that these systems use classical 3D interaction techniques, frequently used in virtual reality (VR). On the other hand, the biological environment is very complex and binding as well. Thus, to remain faithful to the constraintes of the environment and be closer to natural behavior of molecules, we have tried to propose a 3D manipulation adapted to the domain, a bio-supervised 3D manipulation

    Spatial organization of DNA: from the physical data to the 3D model

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    International audienceBehind its spatial organization, the DNA's molecule conceals a rich functional reality. As a result, the study of the DNA's organization is increasingly attracting scientists. However, researches conducted until now are either local, or global but based on approximations and predictions that make the obtained model less credible. On the other hand, further researches on chromosomes' organization have identified some data and models representing, each one, a part of this organization. Our work aims to find a 3D repesentation that is global and more credible of the DNA's molecule. The molecule will be represented at the chromatin fiber level by means of 3D modeling algorithms. Initially, we have identified the biophysical data to be exploited. Indeed, we will first rely on the biophysical data of the chromatin fiber's structure as the persistence length along with the diameter, the confined volume and the curvature energy in order to build a first simple model of the chromatine
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