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Vorlesung Grundlagen der Bioinformatik http://gobics.de/lectures/ss07/grundlagen
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Information from a Single Sequence Alone Sequence alignment in molecular data analysis:
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Information from a Single Sequence Alone Multi-Organism High Quality Sequences Sequence alignment in molecular data analysis: (M. Brudno)
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Tools for multiple sequence alignment seq1 T Y I M R E A Q Y E seq2 T C I V M R E A Y E seq3 Y I M Q E V Q Q E seq4 Y I A M R E Q Y E
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Tools for multiple sequence alignment seq1 T Y I - M R E A Q Y E seq2 T C I V M R E A - Y E seq3 Y - I - M Q E V Q Q E seq4 Y – I A M R E - Q Y E
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Tools for multiple sequence alignment seq1 T Y I - M R E A Q Y E seq2 T C I V M R E A - Y E seq3 Y - I - M Q E V Q Q E seq4 Y – I A M R E - Q Y E
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Tools for multiple sequence alignment seq1 T Y I - M R E A Q Y E seq2 T C I V M R E A - Y E seq3 Y - I - M Q E V Q Q E seq4 Y – I A M R E - Q Y E
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Tools for multiple sequence alignment seq1 T Y I - M R E A Q Y E seq2 T C I V M R E A - Y E seq3 Y - I - M Q E V Q Q E seq4 Y – I A M R E - Q Y E
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Tools for multiple sequence alignment seq1 T Y I - M R E A Q Y E seq2 T C I V M R E A - Y E seq3 Y - I - M Q E V Q Q E seq4 Y – I A M R E - Q Y E Functionally important regions more conserved than non-functional regions
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Tools for multiple sequence alignment seq1 T Y I - M R E A Q Y E seq2 T C I V M R E A - Y E seq3 Y - I - M Q E V Q Q E seq4 Y – I A M R E - Q Y E Functionally important regions more conserved than non-functional regions Local sequence conservation indicates functionality!
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Tools for multiple sequence alignment seq1 T Y I - M R E A Q Y E seq2 T C I V M R E A - Y E seq3 - Y I - M Q E V Q Q E seq4 Y – I A M R E - Q Y E Astronomical Number of possible alignments!
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Tools for multiple sequence alignment seq1 T Y I - M R E A Q Y E seq2 T C I V - M R E A Y E seq3 - Y I - M Q E V Q Q E seq4 Y – I A M R E - Q Y E Astronomical Number of possible alignments!
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Tools for multiple sequence alignment seq1 T Y I - M R E A Q Y E seq2 T C I V M R E A - Y E seq3 - Y I - M Q E V Q Q E seq4 Y – I A M R E - Q Y E Which one is the best ???
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Tools for multiple sequence alignment Questions in development of alignment programs: (1) What is a good alignment? objective function (`score) (2) How to find a good alignment? optimization algorithm First question far more important !
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Tools for multiple sequence alignment Most important scoring scheme for multiple alignment: Sum-of-pairs score for global alignment.
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Divide-and-Conquer Alignment (DCA) J. Stoye, A. Dress (Bielefeld) Approximate optimal global multiple alignment Divide sequences into small sub-sequences Use MSA to calculate optimal alignment for sub- sequences Concatenate sub-alignments
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Divide-and-Conquer Alignment (DCA)
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Tools for multiple sequence alignment Problems with traditional approach: Results depend on gap penalty Heuristic guide tree determines alignment; alignment used for phylogeny reconstruction Algorithm produces global alignments.
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First step in sequence comparison: alignment global alignment (Needleman and Wunsch, 1970; Clustal W) atctaatagttaatactcgtccaagtat atctgtattactaaacaactggtgctacta
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First step in sequence comparison: alignment global alignment (Needleman and Wunsch, 1970; Clustal W) atc--taatagttaat--actcgtccaagtat ||| || || | || ||| || | | || atctgtattact-aaacaactggtgctacta-
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First step in sequence comparison: alignment global alignment (Needleman and Wunsch, 1970; Clustal W) atc--taatagttaat--actcgtccaagtat ||| || || | || ||| || | | || atctgtattact-aaacaactggtgctacta- local alignment (Smith and Waterman, 1983) atctaatagttaatactcgtccaagtat gcgtgtattactaaacggttcaatctaacat
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First step in sequence comparison: alignment global alignment (Needleman and Wunsch, 1970; Clustal W) atc--taatagttaat--actcgtccaagtat ||| || || | || ||| || | | || atctgtattact-aaacaactggtgctacta- local alignment (Smith and Waterman, 1983) atctaatagttaatactcgtccaagtat gcgtgtattactaaacggttcaatctaacat
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First step in sequence comparison: alignment global alignment (Needleman and Wunsch, 1970; Clustal W) atc--taatagttaat--actcgtccaagtat ||| || || | || ||| || | | || atctgtattact-aaacaactggtgctacta- local alignment (Smith and Waterman, 1983) atc--taatagttaatactcgtccaagtat || || | || gcgtgtattact-aaacggttcaatctaacat
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New question: sequence families with multiple local similarities Neither local nor global methods appliccable
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New question: sequence families with multiple local similarities Alignment possible if order conserved
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The DIALIGN approach Morgenstern, Dress, Werner (1996), PNAS 93, 12098-12103 Combination of global and local methods Assemble multiple alignment from gap-free local pair-wise alignments (,,fragments)
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The DIALIGN approach atctaatagttaaactcccccgtgcttag cagtgcgtgtattactaacggttcaatcgcg caaagagtatcacccctgaattgaataa
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The DIALIGN approach atctaatagttaaactcccccgtgcttag cagtgcgtgtattactaacggttcaatcgcg caaagagtatcacccctgaattgaataa
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The DIALIGN approach atctaatagttaaactcccccgtgcttag cagtgcgtgtattactaacggttcaatcgcg caaagagtatcacccctgaattgaataa
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The DIALIGN approach atctaatagttaaactcccccgtgcttag cagtgcgtgtattactaacggttcaatcgcg caaagagtatcacccctgaattgaataa
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The DIALIGN approach atctaatagttaaactcccccgtgcttag cagtgcgtgtattactaacggttcaatcgcg caaagagtatcacccctgaattgaataa
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The DIALIGN approach atctaatagttaaactcccccgtgcttag cagtgcgtgtattactaacggttcaatcgcg caaagagtatcacccctgaattgaataa
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The DIALIGN approach atc------taatagttaaactcccccgtgcttag cagtgcgtgtattactaacggttcaatcgcg caaagagtatcacccctgaattgaataa
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The DIALIGN approach atc------taatagttaaactcccccgtgcttag cagtgcgtgtattactaacggttcaatcgcg caaa--gagtatcacccctgaattgaataa
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The DIALIGN approach atc------taatagttaaactcccccgtgcttag cagtgcgtgtattactaacggttcaatcgcg caaa--gagtatcacc----------cctgaattgaataa
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The DIALIGN approach atc------taatagttaaactcccccgtgc-ttag cagtgcgtgtattactaac----------gg-ttcaatcgcg caaa--gagtatcacc----------cctgaattgaataa
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The DIALIGN approach atc------taatagttaaactcccccgtgc-ttag cagtgcgtgtattactaac----------gg-ttcaatcgcg caaa--gagtatcacc----------cctgaattgaataa Consistency!
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The DIALIGN approach atc------TAATAGTTAaactccccCGTGC-TTag cagtgcGTGTATTACTAAc----------GG-TTCAATcgcg caaa--GAGTATCAcc----------CCTGaaTTGAATaa
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The DIALIGN approach Score of an alignment: Define score of fragment f: l(f) = length of f s(f) = sum of matches (similarity values) P(f) = probability to find a fragment with length l(f) and at least s(f) matches in random sequences that have the same length as the input sequences. Score w(f) = -ln P(f)
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The DIALIGN approach Score of an alignment: Define score of fragment f: Define score of alignment as sum of scores of involved fragments No gap penalty!
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The DIALIGN approach Score of an alignment: Goal in fragment-based alignment approach: find Consistent collection of fragments with maximum sum of weight scores
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The DIALIGN approach atctaatagttaaaccccctcgtgcttagagatccaaac cagtgcgtgtattactaacggttcaatcgcgcacatccgc Pair-wise alignment:
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The DIALIGN approach atctaatagttaaaccccctcgtgcttagagatccaaac cagtgcgtgtattactaacggttcaatcgcgcacatccgc Pair-wise alignment: recursive algorithm finds optimal chain of fragments.
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The DIALIGN approach ------atctaatagttaaaccccctcgtgcttag-------agatccaaac cagtgcgtgtattactaac----------ggttcaatcgcgcacatccgc-- Pair-wise alignment: recursive algorithm finds optimal chain of fragments.
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The DIALIGN approach ------atctaatagttaaaccccctcgtgcttag-------agatccaaac cagtgcgtgtattactaac----------ggttcaatcgcgcacatccgc-- Optimal pairwise alignment: chain of fragments with maximum sum of weights found by dynamic programming: Standard fragment-chaining algorithm Space-efficient algorithm
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The DIALIGN approach Multiple alignment: atctaatagttaaactcccccgtgcttag cagtgcgtgtattactaacggttcaatcgcg caaagagtatcacccctgaattgaataa
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The DIALIGN approach Multiple alignment: atctaatagttaaactcccccgtgcttag cagtgcgtgtattactaacggttcaatcgcg caaccctgaattgaagagtatcacataa (1) Calculate all optimal pair-wise alignments
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The DIALIGN approach Multiple alignment: atctaatagttaaactcccccgtgcttag cagtgcgtgtattactaacggttcaatcgcg caaagagtatcacccctgaattgaataa (1) Calculate all optimal pair-wise alignments
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The DIALIGN approach Multiple alignment: atctaatagttaaactcccccgtgcttag cagtgcgtgtattactaacggttcaatcgcg caaagagtatcacccctgaattgaataa (1) Calculate all optimal pair-wise alignments
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The DIALIGN approach Fragments from optimal pair-wise alignments might be inconsistent
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The DIALIGN approach atctaatagttaaactcccccgtgcttag cagtgcgtgtattactaacggttcaatcgcg caaagagtatcacccctgaattgaataa
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The DIALIGN approach atctaatagttaaactcccccgtgcttag cagtgcgtgtattactaacggttcaatcgcg caaagagtatcacccctgaattgaataa
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The DIALIGN approach atctaatagttaaactcccccgtgcttag cagtgcgtgtattactaacggttcaatcgcg caaagagtatcacccctgaattgaataa
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The DIALIGN approach atctaatagttaaactcccccgtgcttag cagtgcgtgtattactaacggttcaatcgcg caaa--gagtatcacccctgaattgaataa
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The DIALIGN approach atc------taatagttaaactcccccgtgcttag cagtgcgtgtattactaacggttcaatcgcg caaa--gagtatcacccctgaattgaataa
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The DIALIGN approach atctaatagttaaactcccccgtgcttag cagtgcgtgtattactaacggttcaatcgcg caaagagtatcacccctgaattgaataa
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The DIALIGN approach Fragments from optimal pair-wise alignments might be inconsistent 1. Sort fragments according to scores 2. Include them one-by-one into growing multiple alignment – as long as they are consistent (greedy algorithm, comparable to rucksack problem)
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The DIALIGN approach atctaatagttaaactcccccgtgcttag cagtgcgtgtattactaacggttcaatcgcg caaagagtatcacccctgaattgaataa
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The DIALIGN approach atctaatagttaaactcccccgtgcttag cagtgcgtgtattactaacggttcaatcgcg caaagagtatcacccctgaattgaataa
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The DIALIGN approach atctaatagttaaactcccccgtgcttag cagtgcgtgtattactaacggttcaatcgcg caaagagtatcacccctgaattgaataa
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The DIALIGN approach atctaatagttaaactcccccgtgcttag cagtgcgtgtattactaacggttcaatcgcg caaagagtatcacccctgaattgaataa
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The DIALIGN approach atctaatagttaaactcccccgtgcttag cagtgcgtgtattactaacggttcaatcgcg caaagagtatcacccctgaattgaataa Consistency problem
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The DIALIGN approach atctaatagttaaactcccccgtgcttag cagtgcgtgtattactaacggttcaatcgcg caaagagtatcacccctgaattgaataa Consistency problem
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The DIALIGN approach atctaatagttaaactcccccgtgcttag cagtgcgtgtattactaacggttcaatcgcg caaagagtatcacccctgaattgaataa Upper and lower bounds for alignable positions
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The DIALIGN approach atc------taatagttaaactcccccgtgcttag cagtgcgtgtattactaacggttcaatcgcg caaa--gagtatcacccctgaattgaataa Upper and lower bounds for alignable positions
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The DIALIGN approach atc------taatagt taaactcccccgtgcttag Cagtgcgtgtattact aacggttcaatcgcg caaa--gagtatcacccctgaattgaataa Upper and lower bounds for alignable positions
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The DIALIGN approach atc------taata-----gttaaactcccccgtgcttag Cagtgcgtgtatta-----ctaacggttcaatcgcg caaa--gagtatcacccctgaattgaataa Upper and lower bounds for alignable positions
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The DIALIGN approach atctaatagttaaactcccccgtgcttag cagtgcgtgtattactaacggttcaatcgcg caaagagtatcacccctgaattgaataa Upper and lower bounds for alignable positions site x = [i,p] (sequence i, position p)
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The DIALIGN approach atctaatagttaaactcccccgtgcttag cagtgcgtgtattactaacggttcaatcgcg caaagagtatcacccctgaattgaataa Upper and lower bounds for alignable positions Calculate upper bound b l (x,i) and lower bound b u (x,i) for each x and sequence i
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The DIALIGN approach atctaatagttaaactcccccgtgcttag cagtgcgtgtattactaacggttcaatcgcg caaagagtatcacccctgaattgaataa Upper and lower bounds for alignable positions b l (x,i) and b u (x,i) updated for each new fragment in alignment
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The DIALIGN approach Consistency bounds are to be updated for each new fragment that is included in to the growing Alignment Efficient algorithm (Abdeddaim and Morgenstern, 2002)
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The DIALIGN approach Advantages of segment-based approach: Program can produce global and local alignments! Sequence families alignable that cannot be aligned with standard methods
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Program input Program usage: > dialign2-2 [options] = multi-sequence file in FASTA-format
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Program output DIALIGN 2.2.1 ************* Program code written by Burkhard Morgenstern and Said Abdeddaim e-mail contact: bmorgen@gwdg.de Published research assisted by DIALIGN 2 should cite: Burkhard Morgenstern (1999). DIALIGN 2: improvement of the segment-to-segment approach to multiple sequence alignment. Bioinformatics 15, 211 - 218. For more information, please visit the DIALIGN home page at http://bibiserv.techfak.uni-bielefeld.de/dialign/ program call:./dialign2-2 -nt -anc s Aligned sequences: length: ================== ======= 1) dog_il4 300 2) bla 200 3) blu 200 Average seq. length: 233.3 Please note that only upper-case letters are considered to be aligned.
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Program output Alignment (DIALIGN format): =========================== dog_il4 1 cagg------ ----GTTTGA atctgataca ttgc------ ---------- bla 1 ctga------ ---------- ---------- --------GC CAAGTGGGAA blu 1 ttttgatatg agaaGTGTGA aacaagctat cctatattGC TAAGTGGCAG 0000000000 0000000000 0000000000 0000000011 1111111111 dog_il4 25 ---------- --ATGGCACT GGGGTGAATG AGGCAGGCAG CAGAATGATC bla 17 ggtgtgaata catgggtttc cagtaccttc tgaggtccag agtacc---- blu 51 ccctggcttt ctATGTGCAC AGAATGGGAG GAAAGTGCCT GCTAGTGAGC 0000000000 0000000000 0000000000 0000000000 0000000000 dog_il4 63 GTACTGCAGC CCTGAGCTTC CACTGGCCCA TGTTGGTATC CTTGTATTTT bla 63 ---------- ---------- ---TTTCCCA TGTGCTCCAT GGTGGAATGG blu 101 CAGGGACTCA GAGAGAATGG AGTATAGGGG TCAGGGCat- ---------- 0000000000 0000000000 0009999999 9999999888 8888888888 dog_il4 113 TCCGCCCCTT CCCAGCACca gcattatcct ---GGGATTG GAGAAGGGGG bla 90 ACCACTCCTT CTCAGCACaa caaagcccaa gaaGGTGTTG CGTTCTAGAC blu 140 ---------- ---------- ---------- ---GGGGTGG CCTTAGGCTC 8888888888 8888888800 0000000000 0007777777 7777777777
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The DIALIGN approach atctaatagttaaactcccccgtgcttag cagtgcgtgtattactaacggttcaatcgcg caaagagtatcacccctgaattgaataa
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The DIALIGN approach atctaatagttaaactcccccgtgcttag cagtgcgtgtattactaacggttcaatcgcg caaagagtatcacccctgaattgaataa
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The DIALIGN approach atctaatagttaaactcccccgtgcttag cagtgcgtgtattactaacggttcaatcgcg caaagagtatcacccctgaattgaataa
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The DIALIGN approach atctaatagttaaactcccccgtgcttag cagtgcgtgtattactaacggttcaatcgcg caaagagtatcacccctgaattgaataa
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The DIALIGN approach atctaatagttaaactcccccgtgcttag cagtgcgtgtattactaacggttcaatcgcg caaagagtatcacccctgaattgaataa
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The DIALIGN approach atctaatagttaaactcccccgtgcttag cagtgcgtgtattactaacggttcaatcgcg caaagagtatcacccctgaattgaataa
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The DIALIGN approach atc------taatagttaaactcccccgtgcttag cagtgcgtgtattactaacggttcaatcgcg caaagagtatcacccctgaattgaataa
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The DIALIGN approach atc------taatagttaaactcccccgtgcttag cagtgcgtgtattactaacggttcaatcgcg caaa--gagtatcacccctgaattgaataa
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The DIALIGN approach atc------taatagttaaactcccccgtgcttag cagtgcgtgtattactaacggttcaatcgcg caaa--gagtatcacc----------cctgaattgaataa
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The DIALIGN approach atc------taatagttaaactcccccgtgcttag cagtgcgtgtattactaac----------ggttcaatcgcg caaa--gagtatcacc----------cctgaattgaataa
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The DIALIGN approach atc------taatagttaaactcccccgtgc-ttag cagtgcgtgtattactaac----------gg-ttcaatcgcg caaa--gagtatcacc----------cctgaattgaataa
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The DIALIGN approach atc------TAATAGTTAaactccccCGTGC-TTag------ cagtgcGTGTATTACTAAc----------GG-TTCAATcgcg caaa--GAGTATCAcc----------CCTGaaTTGAATaa--
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The DIALIGN approach atc------taatagttaaactcccccgtgc-ttag cagtgcgtgtattactaac----------gg-ttcaatcgcg caaa--gagtatcacc----------cctgaattgaataa
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Alignment of large genomic sequences Fragment-based alignment approach useful for alignment of genomic sequences. Possible applications: Detection of regulatory elements Identification of pathogenic microorganisms Gene prediction
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DIALIGN alignment of human and murine genomic sequences
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DIALIGN alignment of tomato and Thaliana genomic sequences
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Alignment of large genomic sequences Gene-regulatory sites identified by mulitple sequence alignment (phylogenetic footprinting)
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Alignment of large genomic sequences
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Performance of long-range alignment programs for exon discovery (human - mouse comparison)
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Performance of long-range alignment programs for exon discovery (thaliana - tomato comparison)
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