13.07.2015 Views

The Genom of Homo sapiens.pdf

The Genom of Homo sapiens.pdf

The Genom of Homo sapiens.pdf

SHOW MORE
SHOW LESS

Create successful ePaper yourself

Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.

206 ZHANG AND WATERMAN(a)Repeat Repeat Repeat(b)(c)(d)Figure 1. (a) DNA sequence with a triple repeat R; (b) the overlap graph; (c) construction <strong>of</strong> the de Bruijn graph by gluing repeats;(d) de Bruijn graph. (Reprinted, with permission, from Pevzner et al. 2001b.)M fragments, otherwise it is a weak k-tuple. <strong>The</strong> errorcorrection problem is thus to transform the spectrum <strong>of</strong>the original DNA fragments into the spectrum <strong>of</strong> a genomicsequence by changing weak k-tuples to solid k-tuples.Without knowing the real genomic sequence, onenatural criterion <strong>of</strong> error correction is to minimize the totalnumber <strong>of</strong> distinct k-tuples in the spectrum. One errorin a fragment will create at most 2k (including the reversecomplement part) erroneous k-tuples in the spectrum, or2d (d 1. <strong>The</strong> de Bruijn graph correspondingto the original fragments <strong>of</strong> the NM genomeATGCATGTGCATGTATGTGT( a )ATATATGATGTGTGTGTGTGCTGTFigure 2. (a) Two DNA fragments and their 3-tuples (for simplicity,their reverse complements are not included); (b) edgeand vertex presentation <strong>of</strong> those 3-tuples; (c) a de Bruijn graphmade by “gluing” identical edges and vertices.GCGTATATG( b ) ( c )TGTGCTGTGCGT

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!