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BMCBI
2008

Evolution of biological sequences implies an extreme value distribution of type I for both global and local pairwise alignment s

10 years 4 months ago
Evolution of biological sequences implies an extreme value distribution of type I for both global and local pairwise alignment s
Background: Confidence in pairwise alignments of biological sequences, obtained by various methods such as Blast or Smith-Waterman, is critical for automatic analyses of genomic data. Two statistical models have been proposed. In the asymptotic limit of long sequences, the Karlin-Altschul model is based on the computation of a P-value, assuming that the number of high scoring matching regions above a threshold is Poisson distributed. Alternatively, the Lipman-Pearson model is based on the computation of a Z-value from a random score distribution obtained by a Monte-Carlo simulation. Z-values allow the deduction of an upper bound of the P-value (1/Z-value2) following the TULIP theorem. Simulations of Z-value distribution is known to fit with a Gumbel law. This remarkable property was not demonstrated and had no obvious biological support. Results: We built a model of evolution of sequences based on aging, as meant in Reliability Theory, using the fact that the amount of information sha...
Olivier Bastien, Eric Maréchal
Added 09 Dec 2010
Updated 09 Dec 2010
Type Journal
Year 2008
Where BMCBI
Authors Olivier Bastien, Eric Maréchal
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