water.txt

emboss的linux版本的源代码

                                   water 



Function

   Smith-Waterman local alignment

Description

   water uses the Smith-Waterman algorithm (modified for speed
   enhancments) to calculate the local alignment.

   A local alignment searches for regions of local similarity between two
   sequences and need not include the entire length of the sequences.
   Local alignment methods are very useful for scanning databases or
   other circumsatnces when you wish to find matches between small
   regions of sequences, for example between protein domains.

  Algorithm

   The Smith-Waterman algorithm is a member of the class of algorithms
   that can calculate the best score and local alignment in the order of
   mn steps, (where 'n' and 'm' are the lengths of the two sequences).
   These dynamic programming algorithms were first developed for protein
   sequence comparison by Smith and Waterman, though similar methods were
   independently devised during the late 1960's and early 1970's for use
   in the fields of speech processing and computer science.

   Dynamic programming methods ensure the optimal local alignment by
   exploring all possible alignments and choosing the best. It does this
   by reading in a scoring matrix that contains values for every possible
   residue or nucleotide match. water finds an alignment with the maximum
   possible score where the score of an alignment is equal to the sum of
   the matches taken from the scoring matrix.

   An important problem is the treatment of gaps, i.e., spaces inserted
   to optimise the alignment score. A penalty is subtracted from the
   score for each gap opened (the 'gap open' penalty) and a penalty is
   subtracted from the score for the total number of gap spaces
   multiplied by a cost (the 'gap extension' penalty).

   Typically, the cost of extending a gap is set to be 5-10 times lower
   than the cost for opening a gap.

   There are two ways to compute a penalty for a gap of n positions :

gap opening penalty + (n - 1) * gap extension penalty
gap penalty + n * gap length penalty

   The first way is used by EMBOSS and WU-BLAST
   The second way is used by NCBI-BLAST, GCG, Staden and CLUSTAL. Fasta
   used it for a long time the first way, but Prof. Pearson decided
   recently to shift to the second.

   The two methods are basically equivalent.

   The Smith-Waterman algorithm contains no negative scores in the path
   matrix it creates. The algorithm starts the alignment at the highest
   path matrix score and works backwards until a cell contains zero.

   See the Reference Smith et al. for details.

Usage

   Here is a sample session with water


% water tsw:hba_human tsw:hbb_human 
Smith-Waterman local alignment.
Gap opening penalty [10.0]: 
Gap extension penalty [0.5]: 
Output alignment [hba_human.water]: 

   Go to the input files for this example
   Go to the output files for this example

Command line arguments

   Standard (Mandatory) qualifiers:
  [-asequence]         sequence   Sequence filename and optional format, or
                                  reference (input USA)
  [-bsequence]         seqall     Sequence(s) filename and optional format, or
                                  reference (input USA)
   -gapopen            float      [10.0 for any sequence] The gap open penalty
                                  is the score taken away when a gap is
                                  created. The best value depends on the
                                  choice of comparison matrix. The default
                                  value assumes you are using the EBLOSUM62
                                  matrix for protein sequences, and the
                                  EDNAFULL matrix for nucleotide sequences.
                                  (Number from 0.000 to 100.000)
   -gapextend          float      [0.5 for any sequence] The gap extension
                                  penalty is added to the standard gap penalty
                                  for each base or residue in the gap. This
                                  is how long gaps are penalized. Usually you
                                  will expect a few long gaps rather than many
                                  short gaps, so the gap extension penalty
                                  should be lower than the gap penalty. An
                                  exception is where one or both sequences are
                                  single reads with possible sequencing
                                  errors in which case you would expect many
                                  single base gaps. You can get this result by
                                  setting the gap open penalty to zero (or
                                  very low) and using the gap extension
                                  penalty to control gap scoring. (Number from
                                  0.000 to 10.000)
  [-outfile]           align      [*.water] Output alignment file name

   Additional (Optional) qualifiers:
   -datafile           matrixf    [EBLOSUM62 for protein, EDNAFULL for DNA]
                                  This is the scoring matrix file used when
                                  comparing sequences. By default it is the
                                  file 'EBLOSUM62' (for proteins) or the file
                                  'EDNAFULL' (for nucleic sequences). These
                                  files are found in the 'data' directory of
                                  the EMBOSS installation.

   Advanced (Unprompted) qualifiers:
   -[no]brief          boolean    [Y] Brief identity and similarity

   Associated qualifiers:

   "-asequence" associated qualifiers
   -sbegin1            integer    Start of the sequence to be used
   -send1              integer    End of the sequence to be used
   -sreverse1          boolean    Reverse (if DNA)
   -sask1              boolean    Ask for begin/end/reverse
   -snucleotide1       boolean    Sequence is nucleotide
   -sprotein1          boolean    Sequence is protein
   -slower1            boolean    Make lower case
   -supper1            boolean    Make upper case
   -sformat1           string     Input sequence format
   -sdbname1           string     Database name
   -sid1               string     Entryname
   -ufo1               string     UFO features
   -fformat1           string     Features format
   -fopenfile1         string     Features file name

   "-bsequence" associated qualifiers
   -sbegin2            integer    Start of each sequence to be used
   -send2              integer    End of each sequence to be used
   -sreverse2          boolean    Reverse (if DNA)
   -sask2              boolean    Ask for begin/end/reverse
   -snucleotide2       boolean    Sequence is nucleotide
   -sprotein2          boolean    Sequence is protein
   -slower2            boolean    Make lower case
   -supper2            boolean    Make upper case
   -sformat2           string     Input sequence format
   -sdbname2           string     Database name
   -sid2               string     Entryname
   -ufo2               string     UFO features
   -fformat2           string     Features format
   -fopenfile2         string     Features file name

   "-outfile" associated qualifiers
   -aformat3           string     Alignment format
   -aextension3        string     File name extension
   -adirectory3        string     Output directory
   -aname3             string     Base file name
   -awidth3            integer    Alignment width
   -aaccshow3          boolean    Show accession number in the header
   -adesshow3          boolean    Show description in the header
   -ausashow3          boolean    Show the full USA in the alignment
   -aglobal3           boolean    Show the full sequence in alignment

   General qualifiers:
   -auto               boolean    Turn off prompts
   -stdout             boolean    Write standard output
   -filter             boolean    Read standard input, write standard output
   -options            boolean    Prompt for standard and additional values
   -debug              boolean    Write debug output to program.dbg
   -verbose            boolean    Report some/full command line options
   -help               boolean    Report command line options. More
                                  information on associated and general
                                  qualifiers can be found with -help -verbose
   -warning            boolean    Report warnings
   -error              boolean    Report errors
   -fatal              boolean    Report fatal errors
   -die                boolean    Report dying program messages

Input file format

   water reads any two sequence USAs of the same type (DNA or protein).

  Input files for usage example

   'tsw:hba_human' is a sequence entry in the example protein database
   'tsw'

  Database entry: tsw:hba_human

ID   HBA_HUMAN      STANDARD;      PRT;   141 AA.
AC   P01922;
DT   21-JUL-1986 (Rel. 01, Created)
DT   21-JUL-1986 (Rel. 01, Last sequence update)
DT   15-JUL-1999 (Rel. 38, Last annotation update)
DE   HEMOGLOBIN ALPHA CHAIN.
GN   HBA1 AND HBA2.
OS   Homo sapiens (Human), Pan troglodytes (Chimpanzee), and
OS   Pan paniscus (Pygmy chimpanzee) (Bonobo).
OC   Eukaryota; Metazoa; Chordata; Craniata; Vertebrata; Mammalia;
OC   Eutheria; Primates; Catarrhini; Hominidae; Homo.
RN   [1]
RP   SEQUENCE FROM N.A. (ALPHA-1).
RX   MEDLINE; 81088339.
RA   MICHELSON A.M., ORKIN S.H.;
RT   "The 3' untranslated regions of the duplicated human alpha-globin
RT   genes are unexpectedly divergent.";
RL   Cell 22:371-377(1980).
RN   [2]
RP   SEQUENCE FROM N.A. (ALPHA-2).
RX   MEDLINE; 81175088.
RA   LIEBHABER S.A., GOOSSENS M.J., KAN Y.W.;
RT   "Cloning and complete nucleotide sequence of human 5'-alpha-globin
RT   gene.";
RL   Proc. Natl. Acad. Sci. U.S.A. 77:7054-7058(1980).
RN   [3]
RP   SEQUENCE FROM N.A. (ALPHA-2).
RX   MEDLINE; 80137531.
RA   WILSON J.T., WILSON L.B., REDDY V.B., CAVALLESCO C., GHOSH P.K.,
RA   DERIEL J.K., FORGET B.G., WEISSMAN S.M.;
RT   "Nucleotide sequence of the coding portion of human alpha globin
RT   messenger RNA.";
RL   J. Biol. Chem. 255:2807-2815(1980).
RN   [4]
RP   SEQUENCE FROM N.A. (ALPHA-1 AND ALPHA-2).
RA   FLINT J., HIGGS D.R.;
RL   Submitted (JAN-1997) to the EMBL/GenBank/DDBJ databases.
RN   [5]
RP   SEQUENCE.
RA   BRAUNITZER G., GEHRING-MULLER R., HILSCHMANN N., HILSE K., HOBOM G.,
RA   RUDLOFF V., WITTMANN-LIEBOLD B.;
RT   "The constitution of normal adult human haemoglobin.";
RL   Hoppe-Seyler's Z. Physiol. Chem. 325:283-286(1961).
RN   [6]
RP   SEQUENCE.
RA   HILL R.J., KONIGSBERG W.;
RT   "The structure of human hemoglobin: IV. The chymotryptic digestion of
RT   the alpha chain of human hemoglobin.";
RL   J. Biol. Chem. 237:3151-3156(1962).
RN   [7]


  [Part of this file has been deleted for brevity]

FT                                /FTId=VAR_002841.
FT   VARIANT     130    130       A -> D (IN YUDA; O2 AFFINITY DOWN).
FT                                /FTId=VAR_002842.
FT   VARIANT     131    131       S -> P (IN QUESTEMBERT; HIGHLY UNSTABLE;
FT                                CAUSES ALPHA-THALASSEMIA).
FT                                /FTId=VAR_002843.
FT   VARIANT     133    133       S -> R (IN VAL DE MARNE; O2 AFFINITY UP).
FT                                /FTId=VAR_002844.
FT   VARIANT     135    135       V -> E (IN PAVIE).
FT                                /FTId=VAR_002845.
FT   VARIANT     136    136       L -> M (IN CHICAGO).
FT                                /FTId=VAR_002846.
FT   VARIANT     136    136       L -> P (IN BIBBA; UNSTABLE;
FT                                CAUSES ALPHA-THALASSEMIA).
FT                                /FTId=VAR_002847.
FT   VARIANT     138    138       S -> P (IN ATTLEBORO; O2 AFFINITY UP).
FT                                /FTId=VAR_002848.
FT   VARIANT     139    139       K -> E (IN HANAKAMI; O2 AFFINITY UP).
FT                                /FTId=VAR_002849.
FT   VARIANT     139    139       K -> T (IN TOKONAME; O2 AFFINITY UP).
FT                                /FTId=VAR_002850.
FT   VARIANT     140    140       Y -> H (IN ROUEN; O2 AFFINITY UP).
FT                                /FTId=VAR_002851.
FT   VARIANT     141    141       R -> C (IN NUNOBIKI; O2 AFFINITY UP).
FT                                /FTId=VAR_002852.
FT   VARIANT     141    141       R -> L (IN LEGNANO; O2 AFFINITY UP).
FT                                /FTId=VAR_002853.
FT   VARIANT     141    141       R -> H (IN SURESNES; O2 AFFINITY UP).
FT                                /FTId=VAR_002854.
FT   VARIANT     141    141       R -> P (IN SINGAPORE).
FT                                /FTId=VAR_002855.
FT   HELIX         4     35
FT   HELIX        37     42
FT   TURN         44     45
FT   TURN         50     51
FT   HELIX        53     71
FT   TURN         72     74
FT   HELIX        76     79
FT   TURN         80     80
FT   HELIX        81     89
FT   TURN         90     91
FT   TURN         95     95
FT   HELIX        96    112
FT   TURN        114    116
FT   HELIX       119    136
FT   TURN        137    139
SQ   SEQUENCE   141 AA;  15126 MW;  5EC7DB1E CRC32;
     VLSPADKTNV KAAWGKVGAH AGEYGAEALE RMFLSFPTTK TYFPHFDLSH GSAQVKGHGK
     KVADALTNAV AHVDDMPNAL SALSDLHAHK LRVDPVNFKL LSHCLLVTLA AHLPAEFTPA
     VHASLDKFLA SVSTVLTSKY R