1 | |
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2 | This is the on-line help file for CLUSTAL W ( version 1.83). |
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3 | |
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4 | It should be named or defined as: clustalw_help |
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5 | except with MSDOS in which case it should be named CLUSTALW.HLP |
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6 | |
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7 | For full details of usage and algorithms, please read the CLUSTALW.DOC file. |
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8 | |
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9 | |
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10 | Toby Gibson EMBL, Heidelberg, Germany. |
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11 | Des Higgins UCC, Cork, Ireland. |
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12 | Julie Thompson IGBMC, Strasbourg, France. |
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13 | |
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14 | |
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15 | |
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16 | >>NEW << |
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17 | |
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18 | Fasta output |
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19 | =========== |
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20 | |
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21 | Write/Read sequence with range specified. The command line syntax |
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22 | for range specification is flexible. You can use one of the following |
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23 | syntax. |
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24 | |
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25 | -range=n:m |
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26 | -range=n-m |
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27 | -range="n m" |
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28 | |
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29 | where m is the starting and m is the length of the sequence. |
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30 | |
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31 | Range and range numbers. |
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32 | ======================= |
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33 | |
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34 | Include range numbers in the ouput. |
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35 | |
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36 | -seqno_range=on/off |
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37 | |
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38 | The sequence range will be appended as to the names of the sequence. |
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39 | |
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40 | |
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41 | PIM: Percentage Identity Matrix |
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42 | =============================== |
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43 | |
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44 | |
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45 | |
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46 | >>HELP 1 << General help for CLUSTAL W (1.81) |
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47 | |
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48 | Clustal W is a general purpose multiple alignment program for DNA or proteins. |
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49 | |
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50 | SEQUENCE INPUT: all sequences must be in 1 file, one after another. |
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51 | 7 formats are automatically recognised: NBRF-PIR, EMBL-SWISSPROT, |
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52 | Pearson (Fasta), Clustal (*.aln), GCG-MSF (Pileup), GCG9-RSF and GDE flat file. |
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53 | All non-alphabetic characters (spaces, digits, punctuation marks) are ignored |
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54 | except "-" which is used to indicate a GAP ("." in MSF-RSF). |
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55 | |
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56 | To do a MULTIPLE ALIGNMENT on a set of sequences, use item 1 from this menu to |
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57 | INPUT them; go to menu item 2 to do the multiple alignment. |
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58 | |
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59 | PROFILE ALIGNMENTS (menu item 3) are used to align 2 alignments. Use this to |
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60 | add a new sequence to an old alignment, or to use secondary structure to guide |
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61 | the alignment process. GAPS in the old alignments are indicated using the "-" |
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62 | character. PROFILES can be input in ANY of the allowed formats; just |
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63 | use "-" (or "." for MSF-RSF) for each gap position. |
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64 | |
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65 | PHYLOGENETIC TREES (menu item 4) can be calculated from old alignments (read in |
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66 | with "-" characters to indicate gaps) OR after a multiple alignment while the |
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67 | alignment is still in memory. |
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68 | |
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69 | |
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70 | The program tries to automatically recognise the different file formats used |
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71 | and to guess whether the sequences are amino acid or nucleotide. This is not |
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72 | always foolproof. |
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73 | |
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74 | FASTA and NBRF-PIR formats are recognised by having a ">" as the first |
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75 | character in the file. |
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76 | |
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77 | EMBL-Swiss Prot formats are recognised by the letters |
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78 | ID at the start of the file (the token for the entry name field). |
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79 | |
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80 | CLUSTAL format is recognised by the word CLUSTAL at the beginning of the file. |
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81 | |
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82 | GCG-MSF format is recognised by one of the following: |
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83 | - the word PileUp at the start of the file. |
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84 | - the word !!AA_MULTIPLE_ALIGNMENT or !!NA_MULTIPLE_ALIGNMENT |
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85 | at the start of the file. |
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86 | - the word MSF on the first line of the line, and the characters .. |
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87 | at the end of this line. |
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88 | |
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89 | GCG-RSF format is recognised by the word !!RICH_SEQUENCE at the beginning of |
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90 | the file. |
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91 | |
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92 | |
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93 | If 85% or more of the characters in the sequence are from A,C,G,T,U or N, the |
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94 | sequence will be assumed to be nucleotide. This works in 97.3% of cases |
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95 | but watch out! |
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96 | |
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97 | >>HELP 2 << Help for multiple alignments |
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98 | |
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99 | If you have already loaded sequences, use menu item 1 to do the complete |
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100 | multiple alignment. You will be prompted for 2 output files: 1 for the |
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101 | alignment itself; another to store a dendrogram that describes the similarity |
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102 | of the sequences to each other. |
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103 | |
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104 | Multiple alignments are carried out in 3 stages (automatically done from menu |
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105 | item 1 ...Do complete multiple alignments now): |
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106 | |
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107 | 1) all sequences are compared to each other (pairwise alignments); |
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108 | |
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109 | 2) a dendrogram (like a phylogenetic tree) is constructed, describing the |
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110 | approximate groupings of the sequences by similarity (stored in a file). |
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111 | |
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112 | 3) the final multiple alignment is carried out, using the dendrogram as a guide. |
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113 | |
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114 | |
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115 | PAIRWISE ALIGNMENT parameters control the speed-sensitivity of the initial |
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116 | alignments. |
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117 | |
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118 | MULTIPLE ALIGNMENT parameters control the gaps in the final multiple alignments. |
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119 | |
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120 | |
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121 | RESET GAPS (menu item 7) will remove any new gaps introduced into the sequences |
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122 | during multiple alignment if you wish to change the parameters and try again. |
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123 | This only takes effect just before you do a second multiple alignment. You |
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124 | can make phylogenetic trees after alignment whether or not this is ON. |
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125 | If you turn this OFF, the new gaps are kept even if you do a second multiple |
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126 | alignment. This allows you to iterate the alignment gradually. Sometimes, the |
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127 | alignment is improved by a second or third pass. |
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128 | |
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129 | SCREEN DISPLAY (menu item 8) can be used to send the output alignments to the |
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130 | screen as well as to the output file. |
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131 | |
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132 | You can skip the first stages (pairwise alignments; dendrogram) by using an |
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133 | old dendrogram file (menu item 3); or you can just produce the dendrogram |
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134 | with no final multiple alignment (menu item 2). |
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135 | |
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136 | |
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137 | OUTPUT FORMAT: Menu item 9 (format options) allows you to choose from 6 |
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138 | different alignment formats (CLUSTAL, GCG, NBRF-PIR, PHYLIP, GDE, NEXUS, and FASTA). |
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139 | |
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140 | |
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141 | >>HELP 3 << Help for pairwise alignment parameters |
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142 | A distance is calculated between every pair of sequences and these are used to |
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143 | construct the dendrogram which guides the final multiple alignment. The scores |
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144 | are calculated from separate pairwise alignments. These can be calculated using |
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145 | 2 methods: dynamic programming (slow but accurate) or by the method of Wilbur |
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146 | and Lipman (extremely fast but approximate). |
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147 | |
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148 | You can choose between the 2 alignment methods using menu option 8. The |
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149 | slow-accurate method is fine for short sequences but will be VERY SLOW for |
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150 | many (e.g. >100) long (e.g. >1000 residue) sequences. |
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151 | |
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152 | SLOW-ACCURATE alignment parameters: |
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153 | These parameters do not have any affect on the speed of the alignments. |
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154 | They are used to give initial alignments which are then rescored to give percent |
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155 | identity scores. These % scores are the ones which are displayed on the |
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156 | screen. The scores are converted to distances for the trees. |
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157 | |
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158 | 1) Gap Open Penalty: the penalty for opening a gap in the alignment. |
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159 | 2) Gap extension penalty: the penalty for extending a gap by 1 residue. |
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160 | 3) Protein weight matrix: the scoring table which describes the similarity |
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161 | of each amino acid to each other. |
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162 | 4) DNA weight matrix: the scores assigned to matches and mismatches |
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163 | (including IUB ambiguity codes). |
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164 | |
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165 | |
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166 | FAST-APPROXIMATE alignment parameters: |
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167 | |
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168 | These similarity scores are calculated from fast, approximate, global alignments, |
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169 | which are controlled by 4 parameters. 2 techniques are used to make |
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170 | these alignments very fast: 1) only exactly matching fragments (k-tuples) are |
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171 | considered; 2) only the 'best' diagonals (the ones with most k-tuple matches) |
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172 | are used. |
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173 | |
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174 | K-TUPLE SIZE: This is the size of exactly matching fragment that is used. |
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175 | INCREASE for speed (max= 2 for proteins; 4 for DNA), DECREASE for sensitivity. |
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176 | For longer sequences (e.g. >1000 residues) you may need to increase the default. |
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177 | |
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178 | GAP PENALTY: This is a penalty for each gap in the fast alignments. It has |
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179 | little affect on the speed or sensitivity except for extreme values. |
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180 | |
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181 | TOP DIAGONALS: The number of k-tuple matches on each diagonal (in an imaginary |
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182 | dot-matrix plot) is calculated. Only the best ones (with most matches) are |
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183 | used in the alignment. This parameter specifies how many. Decrease for speed; |
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184 | increase for sensitivity. |
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185 | |
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186 | WINDOW SIZE: This is the number of diagonals around each of the 'best' |
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187 | diagonals that will be used. Decrease for speed; increase for sensitivity. |
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188 | |
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189 | |
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190 | >>HELP 4 << Help for multiple alignment parameters |
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191 | |
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192 | These parameters control the final multiple alignment. This is the core of the |
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193 | program and the details are complicated. To fully understand the use of the |
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194 | parameters and the scoring system, you will have to refer to the documentation. |
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195 | |
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196 | Each step in the final multiple alignment consists of aligning two alignments |
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197 | or sequences. This is done progressively, following the branching order in |
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198 | the GUIDE TREE. The basic parameters to control this are two gap penalties and |
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199 | the scores for various identical-non-identical residues. |
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200 | |
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201 | 1) and .. |
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202 | |
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203 | 2) The GAP PENALTIES are set by menu items 1 and 2. These control the |
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204 | cost of opening up every new gap and the cost of every item in a gap. |
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205 | Increasing the gap opening penalty will make gaps less frequent. Increasing |
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206 | the gap extension penalty will make gaps shorter. Terminal gaps are not |
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207 | penalised. |
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208 | |
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209 | 3) The DELAY DIVERGENT SEQUENCES switch delays the alignment of the most |
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210 | distantly related sequences until after the most closely related sequences have |
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211 | been aligned. The setting shows the percent identity level required to delay |
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212 | the addition of a sequence; sequences that are less identical than this level |
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213 | to any other sequences will be aligned later. |
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214 | |
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215 | |
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216 | |
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217 | 4) The TRANSITION WEIGHT gives transitions (A <--> G or C <--> T |
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218 | i.e. purine-purine or pyrimidine-pyrimidine substitutions) a weight between 0 |
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219 | and 1; a weight of zero means that the transitions are scored as mismatches, |
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220 | while a weight of 1 gives the transitions the match score. For distantly related |
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221 | DNA sequences, the weight should be near to zero; for closely related sequences |
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222 | it can be useful to assign a higher score. |
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223 | |
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224 | |
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225 | 5) PROTEIN WEIGHT MATRIX leads to a new menu where you are offered a choice of |
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226 | weight matrices. The default for proteins in version 1.8 is the PAM series |
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227 | derived by Gonnet and colleagues. Note, a series is used! The actual matrix |
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228 | that is used depends on how similar the sequences to be aligned at this |
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229 | alignment step are. Different matrices work differently at each evolutionary |
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230 | distance. |
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231 | |
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232 | 6) DNA WEIGHT MATRIX leads to a new menu where a single matrix (not a series) |
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233 | can be selected. The default is the matrix used by BESTFIT for comparison of |
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234 | nucleic acid sequences. |
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235 | |
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236 | Further help is offered in the weight matrix menu. |
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237 | |
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238 | |
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239 | 7) In the weight matrices, you can use negative as well as positive values if |
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240 | you wish, although the matrix will be automatically adjusted to all positive |
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241 | scores, unless the NEGATIVE MATRIX option is selected. |
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242 | |
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243 | 8) PROTEIN GAP PARAMETERS displays a menu allowing you to set some Gap Penalty |
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244 | options which are only used in protein alignments. |
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245 | |
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246 | |
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247 | >>HELP A << Help for protein gap parameters. |
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248 | 1) RESIDUE SPECIFIC PENALTIES are amino acid specific gap penalties that reduce |
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249 | or increase the gap opening penalties at each position in the alignment or |
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250 | sequence. See the documentation for details. As an example, positions that |
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251 | are rich in glycine are more likely to have an adjacent gap than positions that |
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252 | are rich in valine. |
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253 | |
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254 | 2) [and ..] |
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255 | |
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256 | 3) HYDROPHILIC GAP PENALTIES are used to increase the chances of a gap within |
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257 | a run (5 or more residues) of hydrophilic amino acids; these are likely to |
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258 | be loop or random coil regions where gaps are more common. The residues that |
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259 | are "considered" to be hydrophilic are set by menu item 3. |
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260 | |
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261 | 4) GAP SEPARATION DISTANCE tries to decrease the chances of gaps being too |
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262 | close to each other. Gaps that are less than this distance apart are penalised |
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263 | more than other gaps. This does not prevent close gaps; it makes them less |
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264 | frequent, promoting a block-like appearance of the alignment. |
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265 | |
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266 | 5) END GAP SEPARATION treats end gaps just like internal gaps for the purposes |
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267 | of avoiding gaps that are too close (set by GAP SEPARATION DISTANCE above). |
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268 | If you turn this off, end gaps will be ignored for this purpose. This is |
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269 | useful when you wish to align fragments where the end gaps are not biologically |
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270 | meaningful. |
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271 | >>HELP 5 << Help for output format options. |
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272 | |
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273 | Six output formats are offered. You can choose any (or all 6 if you wish). |
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274 | |
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275 | CLUSTAL format output is a self explanatory alignment format. It shows the |
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276 | sequences aligned in blocks. It can be read in again at a later date to |
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277 | (for example) calculate a phylogenetic tree or add a new sequence with a |
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278 | profile alignment. |
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279 | |
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280 | GCG output can be used by any of the GCG programs that can work on multiple |
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281 | alignments (e.g. PRETTY, PROFILEMAKE, PLOTALIGN). It is the same as the GCG |
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282 | .msf format files (multiple sequence file); new in version 7 of GCG. |
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283 | |
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284 | PHYLIP format output can be used for input to the PHYLIP package of Joe |
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285 | Felsenstein. This is an extremely widely used package for doing every |
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286 | imaginable form of phylogenetic analysis (MUCH more than the the modest |
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287 | introduction offered by this program). |
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288 | |
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289 | NBRF-PIR: this is the same as the standard PIR format with ONE ADDITION. Gap |
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290 | characters "-" are used to indicate the positions of gaps in the multiple |
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291 | alignment. These files can be re-used as input in any part of clustal that |
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292 | allows sequences (or alignments or profiles) to be read in. |
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293 | |
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294 | GDE: this is the flat file format used by the GDE package of Steven Smith. |
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295 | |
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296 | NEXUS: the format used by several phylogeny programs, including PAUP and |
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297 | MacClade. |
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298 | |
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299 | GDE OUTPUT CASE: sequences in GDE format may be written in either upper or |
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300 | lower case. |
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301 | |
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302 | CLUSTALW SEQUENCE NUMBERS: residue numbers may be added to the end of the |
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303 | alignment lines in clustalw format. |
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304 | |
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305 | OUTPUT ORDER is used to control the order of the sequences in the output |
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306 | alignments. By default, the order corresponds to the order in which the |
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307 | sequences were aligned (from the guide tree-dendrogram), thus automatically |
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308 | grouping closely related sequences. This switch can be used to set the order |
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309 | to the same as the input file. |
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310 | |
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311 | PARAMETER OUTPUT: This option allows you to save all your parameter settings |
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312 | in a parameter file. This file can be used subsequently to rerun Clustal W |
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313 | using the same parameters. |
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314 | |
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315 | >>HELP 6 << Help for profile and structure alignments |
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316 | |
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317 | By PROFILE ALIGNMENT, we mean alignment using existing alignments. Profile |
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318 | alignments allow you to store alignments of your favourite sequences and add |
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319 | new sequences to them in small bunches at a time. A profile is simply an |
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320 | alignment of one or more sequences (e.g. an alignment output file from CLUSTAL |
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321 | W). Each input can be a single sequence. One or both sets of input sequences |
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322 | may include secondary structure assignments or gap penalty masks to guide the |
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323 | alignment. |
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324 | |
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325 | The profiles can be in any of the allowed input formats with "-" characters |
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326 | used to specify gaps (except for MSF-RSF where "." is used). |
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327 | |
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328 | You have to specify the 2 profiles by choosing menu items 1 and 2 and giving |
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329 | 2 file names. Then Menu item 3 will align the 2 profiles to each other. |
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330 | Secondary structure masks in either profile can be used to guide the alignment. |
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331 | |
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332 | Menu item 4 will take the sequences in the second profile and align them to |
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333 | the first profile, 1 at a time. This is useful to add some new sequences to |
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334 | an existing alignment, or to align a set of sequences to a known structure. |
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335 | In this case, the second profile would not be pre-aligned. |
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336 | |
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337 | |
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338 | The alignment parameters can be set using menu items 5, 6 and 7. These are |
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339 | EXACTLY the same parameters as used by the general, automatic multiple |
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340 | alignment procedure. The general multiple alignment procedure is simply a |
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341 | series of profile alignments. Carrying out a series of profile alignments on |
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342 | larger and larger groups of sequences, allows you to manually build up a |
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343 | complete alignment, if necessary editing intermediate alignments. |
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344 | |
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345 | SECONDARY STRUCTURE OPTIONS. Menu Option 0 allows you to set 2D structure |
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346 | parameters. If a solved structure is available, it can be used to guide the |
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347 | alignment by raising gap penalties within secondary structure elements, so |
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348 | that gaps will preferentially be inserted into unstructured surface loops. |
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349 | Alternatively, a user-specified gap penalty mask can be supplied directly. |
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350 | |
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351 | A gap penalty mask is a series of numbers between 1 and 9, one per position in |
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352 | the alignment. Each number specifies how much the gap opening penalty is to be |
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353 | raised at that position (raised by multiplying the basic gap opening penalty |
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354 | by the number) i.e. a mask figure of 1 at a position means no change |
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355 | in gap opening penalty; a figure of 4 means that the gap opening penalty is |
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356 | four times greater at that position, making gaps 4 times harder to open. |
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357 | |
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358 | The format for gap penalty masks and secondary structure masks is explained |
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359 | in the help under option 0 (secondary structure options). |
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360 | >>HELP B << Help for secondary structure - gap penalty masks |
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361 | |
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362 | The use of secondary structure-based penalties has been shown to improve the |
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363 | accuracy of multiple alignment. Therefore CLUSTAL W now allows gap penalty |
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364 | masks to be supplied with the input sequences. The masks work by raising gap |
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365 | penalties in specified regions (typically secondary structure elements) so that |
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366 | gaps are preferentially opened in the less well conserved regions (typically |
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367 | surface loops). |
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368 | |
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369 | Options 1 and 2 control whether the input secondary structure information or |
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370 | gap penalty masks will be used. |
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371 | |
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372 | Option 3 controls whether the secondary structure and gap penalty masks should |
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373 | be included in the output alignment. |
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374 | |
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375 | Options 4 and 5 provide the value for raising the gap penalty at core Alpha |
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376 | Helical (A) and Beta Strand (B) residues. In CLUSTAL format, capital residues |
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377 | denote the A and B core structure notation. The basic gap penalties are |
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378 | multiplied by the amount specified. |
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379 | |
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380 | Option 6 provides the value for the gap penalty in Loops. By default this |
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381 | penalty is not raised. In CLUSTAL format, loops are specified by "." in the |
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382 | secondary structure notation. |
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383 | |
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384 | Option 7 provides the value for setting the gap penalty at the ends of |
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385 | secondary structures. Ends of secondary structures are observed to grow |
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386 | and-or shrink in related structures. Therefore by default these are given |
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387 | intermediate values, lower than the core penalties. All secondary structure |
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388 | read in as lower case in CLUSTAL format gets the reduced terminal penalty. |
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389 | |
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390 | Options 8 and 9 specify the range of structure termini for the intermediate |
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391 | penalties. In the alignment output, these are indicated as lower case. |
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392 | For Alpha Helices, by default, the range spans the end helical turn. For |
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393 | Beta Strands, the default range spans the end residue and the adjacent loop |
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394 | residue, since sequence conservation often extends beyond the actual H-bonded |
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395 | Beta Strand. |
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396 | |
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397 | CLUSTAL W can read the masks from SWISS-PROT, CLUSTAL or GDE format input |
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398 | files. For many 3-D protein structures, secondary structure information is |
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399 | recorded in the feature tables of SWISS-PROT database entries. You should |
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400 | always check that the assignments are correct - some are quite inaccurate. |
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401 | CLUSTAL W looks for SWISS-PROT HELIX and STRAND assignments e.g. |
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402 | |
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403 | FT HELIX 100 115 |
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404 | FT STRAND 118 119 |
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405 | |
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406 | The structure and penalty masks can also be read from CLUSTAL alignment format |
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407 | as comment lines beginning "!SS_" or "!GM_" e.g. |
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408 | |
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409 | !SS_HBA_HUMA ..aaaAAAAAAAAAAaaa.aaaAAAAAAAAAAaaaaaaAaaa.........aaaAAAAAA |
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410 | !GM_HBA_HUMA 112224444444444222122244444444442222224222111111111222444444 |
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411 | HBA_HUMA VLSPADKTNVKAAWGKVGAHAGEYGAEALERMFLSFPTTKTYFPHFDLSHGSAQVKGHGK |
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412 | |
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413 | Note that the mask itself is a set of numbers between 1 and 9 each of which is |
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414 | assigned to the residue(s) in the same column below. |
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415 | |
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416 | In GDE flat file format, the masks are specified as text and the names must |
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417 | begin with "SS_ or "GM_. |
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418 | |
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419 | Either a structure or penalty mask or both may be used. If both are included in |
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420 | an alignment, the user will be asked which is to be used. |
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421 | |
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422 | >>HELP C << Help for secondary structure - gap penalty mask output options |
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423 | |
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424 | The options in this menu let you choose whether or not to include the masks |
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425 | in the CLUSTAL W output alignments. Showing both is useful for understanding |
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426 | how the masks work. The secondary structure information is itself very useful |
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427 | in judging the alignment quality and in seeing how residue conservation |
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428 | patterns vary with secondary structure. |
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429 | |
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430 | |
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431 | >>HELP 7 << Help for phylogenetic trees |
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432 | |
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433 | 1) Before calculating a tree, you must have an ALIGNMENT in memory. This can be |
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434 | input in any format or you should have just carried out a full multiple |
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435 | alignment and the alignment is still in memory. |
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436 | |
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437 | |
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438 | *************** Remember YOU MUST ALIGN THE SEQUENCES FIRST!!!! *************** |
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439 | |
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440 | |
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441 | The method used is the NJ (Neighbour Joining) method of Saitou and Nei. First |
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442 | you calculate distances (percent divergence) between all pairs of sequence from |
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443 | a multiple alignment; second you apply the NJ method to the distance matrix. |
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444 | |
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445 | 2) EXCLUDE POSITIONS WITH GAPS? With this option, any alignment positions where |
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446 | ANY of the sequences have a gap will be ignored. This means that 'like' will be |
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447 | compared to 'like' in all distances, which is highly desirable. It also |
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448 | automatically throws away the most ambiguous parts of the alignment, which are |
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449 | concentrated around gaps (usually). The disadvantage is that you may throw away |
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450 | much of the data if there are many gaps (which is why it is difficult for us to |
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451 | make it the default). |
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452 | |
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453 | |
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454 | |
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455 | 3) CORRECT FOR MULTIPLE SUBSTITUTIONS? For small divergence (say <10%) this |
---|
456 | option makes no difference. For greater divergence, it corrects for the fact |
---|
457 | that observed distances underestimate actual evolutionary distances. This is |
---|
458 | because, as sequences diverge, more than one substitution will happen at many |
---|
459 | sites. However, you only see one difference when you look at the present day |
---|
460 | sequences. Therefore, this option has the effect of stretching branch lengths |
---|
461 | in trees (especially long branches). The corrections used here (for DNA or |
---|
462 | proteins) are both due to Motoo Kimura. See the documentation for details. |
---|
463 | |
---|
464 | Where possible, this option should be used. However, for VERY divergent |
---|
465 | sequences, the distances cannot be reliably corrected. You will be warned if |
---|
466 | this happens. Even if none of the distances in a data set exceed the reliable |
---|
467 | threshold, if you bootstrap the data, some of the bootstrap distances may |
---|
468 | randomly exceed the safe limit. |
---|
469 | |
---|
470 | 4) To calculate a tree, use option 4 (DRAW TREE NOW). This gives an UNROOTED |
---|
471 | tree and all branch lengths. The root of the tree can only be inferred by |
---|
472 | using an outgroup (a sequence that you are certain branches at the outside |
---|
473 | of the tree .... certain on biological grounds) OR if you assume a degree |
---|
474 | of constancy in the 'molecular clock', you can place the root in the 'middle' |
---|
475 | of the tree (roughly equidistant from all tips). |
---|
476 | |
---|
477 | 5) TOGGLE PHYLIP BOOTSTRAP POSITIONS |
---|
478 | By default, the bootstrap values are correctly placed on the tree branches of |
---|
479 | the phylip format output tree. The toggle allows them to be placed on the |
---|
480 | nodes, which is incorrect, but some display packages (e.g. TreeTool, TreeView |
---|
481 | and Phylowin) only support node labelling but not branch labelling. Care |
---|
482 | should be taken to note which branches and labels go together. |
---|
483 | |
---|
484 | 6) OUTPUT FORMATS: four different formats are allowed. None of these displays |
---|
485 | the tree visually. Useful display programs accepting PHYLIP format include |
---|
486 | NJplot (from Manolo Gouy and supplied with Clustal W), TreeView (Mac-PC), and |
---|
487 | PHYLIP itself - OR get the PHYLIP package and use the tree drawing facilities |
---|
488 | there. (Get the PHYLIP package anyway if you are interested in trees). The |
---|
489 | NEXUS format can be read into PAUP or MacClade. |
---|
490 | |
---|
491 | >>HELP 8 << Help for choosing a weight matrix |
---|
492 | |
---|
493 | For protein alignments, you use a weight matrix to determine the similarity of |
---|
494 | non-identical amino acids. For example, Tyr aligned with Phe is usually judged |
---|
495 | to be 'better' than Tyr aligned with Pro. |
---|
496 | |
---|
497 | There are three 'in-built' series of weight matrices offered. Each consists of |
---|
498 | several matrices which work differently at different evolutionary distances. To |
---|
499 | see the exact details, read the documentation. Crudely, we store several |
---|
500 | matrices in memory, spanning the full range of amino acid distance (from almost |
---|
501 | identical sequences to highly divergent ones). For very similar sequences, it |
---|
502 | is best to use a strict weight matrix which only gives a high score to |
---|
503 | identities and the most favoured conservative substitutions. For more divergent |
---|
504 | sequences, it is appropriate to use "softer" matrices which give a high score |
---|
505 | to many other frequent substitutions. |
---|
506 | |
---|
507 | 1) BLOSUM (Henikoff). These matrices appear to be the best available for |
---|
508 | carrying out database similarity (homology searches). The matrices used are: |
---|
509 | Blosum 80, 62, 45 and 30. (BLOSUM was the default in earlier Clustal W |
---|
510 | versions) |
---|
511 | |
---|
512 | 2) PAM (Dayhoff). These have been extremely widely used since the late '70s. |
---|
513 | We use the PAM 20, 60, 120 and 350 matrices. |
---|
514 | |
---|
515 | 3) GONNET. These matrices were derived using almost the same procedure as the |
---|
516 | Dayhoff one (above) but are much more up to date and are based on a far larger |
---|
517 | data set. They appear to be more sensitive than the Dayhoff series. We use the |
---|
518 | GONNET 80, 120, 160, 250 and 350 matrices. This series is the default for |
---|
519 | Clustal W version 1.8. |
---|
520 | |
---|
521 | We also supply an identity matrix which gives a score of 1.0 to two identical |
---|
522 | amino acids and a score of zero otherwise. This matrix is not very useful. |
---|
523 | Alternatively, you can read in your own (just one matrix, not a series). |
---|
524 | |
---|
525 | A new matrix can be read from a file on disk, if the filename consists only |
---|
526 | of lower case characters. The values in the new weight matrix must be integers |
---|
527 | and the scores should be similarities. You can use negative as well as positive |
---|
528 | values if you wish, although the matrix will be automatically adjusted to all |
---|
529 | positive scores. |
---|
530 | |
---|
531 | |
---|
532 | |
---|
533 | For DNA, a single matrix (not a series) is used. Two hard-coded matrices are |
---|
534 | available: |
---|
535 | |
---|
536 | |
---|
537 | 1) IUB. This is the default scoring matrix used by BESTFIT for the comparison |
---|
538 | of nucleic acid sequences. X's and N's are treated as matches to any IUB |
---|
539 | ambiguity symbol. All matches score 1.9; all mismatches for IUB symbols score 0. |
---|
540 | |
---|
541 | |
---|
542 | 2) CLUSTALW(1.6). The previous system used by Clustal W, in which matches score |
---|
543 | 1.0 and mismatches score 0. All matches for IUB symbols also score 0. |
---|
544 | |
---|
545 | INPUT FORMAT The format used for a new matrix is the same as the BLAST program. |
---|
546 | Any lines beginning with a # character are assumed to be comments. The first |
---|
547 | non-comment line should contain a list of amino acids in any order, using the |
---|
548 | 1 letter code, followed by a * character. This should be followed by a square |
---|
549 | matrix of integer scores, with one row and one column for each amino acid. The |
---|
550 | last row and column of the matrix (corresponding to the * character) contain |
---|
551 | the minimum score over the whole matrix. |
---|
552 | |
---|
553 | >>HELP 9 << Help for command line parameters |
---|
554 | DATA (sequences) |
---|
555 | |
---|
556 | -INFILE=file.ext :input sequences. |
---|
557 | -PROFILE1=file.ext and -PROFILE2=file.ext :profiles (old alignment). |
---|
558 | |
---|
559 | |
---|
560 | VERBS (do things) |
---|
561 | |
---|
562 | -OPTIONS :list the command line parameters |
---|
563 | -HELP or -CHECK :outline the command line params. |
---|
564 | -ALIGN :do full multiple alignment |
---|
565 | -TREE :calculate NJ tree. |
---|
566 | -BOOTSTRAP(=n) :bootstrap a NJ tree (n= number of bootstraps; def. = 1000). |
---|
567 | -CONVERT :output the input sequences in a different file format. |
---|
568 | |
---|
569 | |
---|
570 | PARAMETERS (set things) |
---|
571 | |
---|
572 | ***General settings:**** |
---|
573 | -INTERACTIVE :read command line, then enter normal interactive menus |
---|
574 | -QUICKTREE :use FAST algorithm for the alignment guide tree |
---|
575 | -TYPE= :PROTEIN or DNA sequences |
---|
576 | -NEGATIVE :protein alignment with negative values in matrix |
---|
577 | -OUTFILE= :sequence alignment file name |
---|
578 | -OUTPUT= :GCG, GDE, PHYLIP, PIR or NEXUS |
---|
579 | -OUTORDER= :INPUT or ALIGNED |
---|
580 | -CASE :LOWER or UPPER (for GDE output only) |
---|
581 | -SEQNOS= :OFF or ON (for Clustal output only) |
---|
582 | -SEQNO_RANGE=:OFF or ON (NEW: for all output formats) |
---|
583 | -RANGE=m,n :sequence range to write starting m to m+n. |
---|
584 | |
---|
585 | ***Fast Pairwise Alignments:*** |
---|
586 | -KTUPLE=n :word size |
---|
587 | -TOPDIAGS=n :number of best diags. |
---|
588 | -WINDOW=n :window around best diags. |
---|
589 | -PAIRGAP=n :gap penalty |
---|
590 | -SCORE :PERCENT or ABSOLUTE |
---|
591 | |
---|
592 | |
---|
593 | ***Slow Pairwise Alignments:*** |
---|
594 | -PWMATRIX= :Protein weight matrix=BLOSUM, PAM, GONNET, ID or filename |
---|
595 | -PWDNAMATRIX= :DNA weight matrix=IUB, CLUSTALW or filename |
---|
596 | -PWGAPOPEN=f :gap opening penalty |
---|
597 | -PWGAPEXT=f :gap opening penalty |
---|
598 | |
---|
599 | |
---|
600 | ***Multiple Alignments:*** |
---|
601 | -NEWTREE= :file for new guide tree |
---|
602 | -USETREE= :file for old guide tree |
---|
603 | -MATRIX= :Protein weight matrix=BLOSUM, PAM, GONNET, ID or filename |
---|
604 | -DNAMATRIX= :DNA weight matrix=IUB, CLUSTALW or filename |
---|
605 | -GAPOPEN=f :gap opening penalty |
---|
606 | -GAPEXT=f :gap extension penalty |
---|
607 | -ENDGAPS :no end gap separation pen. |
---|
608 | -GAPDIST=n :gap separation pen. range |
---|
609 | -NOPGAP :residue-specific gaps off |
---|
610 | -NOHGAP :hydrophilic gaps off |
---|
611 | -HGAPRESIDUES= :list hydrophilic res. |
---|
612 | -MAXDIV=n :% ident. for delay |
---|
613 | -TYPE= :PROTEIN or DNA |
---|
614 | -TRANSWEIGHT=f :transitions weighting |
---|
615 | |
---|
616 | |
---|
617 | ***Profile Alignments:*** |
---|
618 | -PROFILE :Merge two alignments by profile alignment |
---|
619 | -NEWTREE1= :file for new guide tree for profile1 |
---|
620 | -NEWTREE2= :file for new guide tree for profile2 |
---|
621 | -USETREE1= :file for old guide tree for profile1 |
---|
622 | -USETREE2= :file for old guide tree for profile2 |
---|
623 | |
---|
624 | |
---|
625 | ***Sequence to Profile Alignments:*** |
---|
626 | -SEQUENCES :Sequentially add profile2 sequences to profile1 alignment |
---|
627 | -NEWTREE= :file for new guide tree |
---|
628 | -USETREE= :file for old guide tree |
---|
629 | |
---|
630 | |
---|
631 | ***Structure Alignments:*** |
---|
632 | -NOSECSTR1 :do not use secondary structure-gap penalty mask for profile 1 |
---|
633 | -NOSECSTR2 :do not use secondary structure-gap penalty mask for profile 2 |
---|
634 | -SECSTROUT=STRUCTURE or MASK or BOTH or NONE :output in alignment file |
---|
635 | -HELIXGAP=n :gap penalty for helix core residues |
---|
636 | -STRANDGAP=n :gap penalty for strand core residues |
---|
637 | -LOOPGAP=n :gap penalty for loop regions |
---|
638 | -TERMINALGAP=n :gap penalty for structure termini |
---|
639 | -HELIXENDIN=n :number of residues inside helix to be treated as terminal |
---|
640 | -HELIXENDOUT=n :number of residues outside helix to be treated as terminal |
---|
641 | -STRANDENDIN=n :number of residues inside strand to be treated as terminal |
---|
642 | -STRANDENDOUT=n:number of residues outside strand to be treated as terminal |
---|
643 | |
---|
644 | |
---|
645 | ***Trees:*** |
---|
646 | -OUTPUTTREE=nj OR phylip OR dist OR nexus |
---|
647 | -SEED=n :seed number for bootstraps. |
---|
648 | -KIMURA :use Kimura's correction. |
---|
649 | -TOSSGAPS :ignore positions with gaps. |
---|
650 | -BOOTLABELS=node OR branch :position of bootstrap values in tree display |
---|
651 | |
---|
652 | >>HELP 0 << Help for tree output format options |
---|
653 | |
---|
654 | Four output formats are offered: |
---|
655 | 1) Clustal, |
---|
656 | 2) Phylip, |
---|
657 | 3) Just the distances |
---|
658 | 4) Nexus |
---|
659 | |
---|
660 | None of these formats displays the results graphically. Many packages can |
---|
661 | display trees in the the PHYLIP format 2) below. It can also be imported into |
---|
662 | the PHYLIP programs RETREE, DRAWTREE and DRAWGRAM for graphical display. |
---|
663 | NEXUS format trees can be read by PAUP and MacClade. |
---|
664 | |
---|
665 | 1) Clustal format output. |
---|
666 | |
---|
667 | This format is verbose and lists all of the distances between the sequences and |
---|
668 | the number of alignment positions used for each. The tree is described at the |
---|
669 | end of the file. It lists the sequences that are joined at each alignment step |
---|
670 | and the branch lengths. After two sequences are joined, it is referred to later |
---|
671 | as a NODE. The number of a NODE is the number of the lowest sequence in that |
---|
672 | NODE. |
---|
673 | |
---|
674 | 2) Phylip format output. |
---|
675 | |
---|
676 | This format is the New Hampshire format, used by many phylogenetic analysis |
---|
677 | packages. It consists of a series of nested parentheses, describing the |
---|
678 | branching order, with the sequence names and branch lengths. It can be used by |
---|
679 | the RETREE, DRAWGRAM and DRAWTREE programs of the PHYLIP package to see the |
---|
680 | trees graphically. This is the same format used during multiple alignment for |
---|
681 | the guide trees. |
---|
682 | |
---|
683 | Use this format with NJplot (Manolo Gouy), supplied with Clustal W. Some other |
---|
684 | packages that can read and display New Hampshire format are TreeView (Mac/PC), |
---|
685 | TreeTool (UNIX), and Phylowin. |
---|
686 | |
---|
687 | 3) The distances only. |
---|
688 | |
---|
689 | This format just outputs a matrix of all the pairwise distances in a format |
---|
690 | that can be used by the Phylip package. It used to be useful when one could not |
---|
691 | produce distances from protein sequences in the Phylip package but is now |
---|
692 | redundant (Protdist of Phylip 3.5 now does this). |
---|
693 | |
---|
694 | 4) NEXUS FORMAT TREE. |
---|
695 | |
---|
696 | This format is used by several popular phylogeny programs, |
---|
697 | including PAUP and MacClade. The format is described fully in: |
---|
698 | Maddison, D. R., D. L. Swofford and W. P. Maddison. 1997. |
---|
699 | NEXUS: an extensible file format for systematic information. |
---|
700 | Systematic Biology 46:590-621. |
---|
701 | |
---|
702 | 5) TOGGLE PHYLIP BOOTSTRAP POSITIONS |
---|
703 | |
---|
704 | By default, the bootstrap values are placed on the nodes of the phylip format |
---|
705 | output tree. This is inaccurate as the bootstrap values should be associated |
---|
706 | with the tree branches and not the nodes. However, this format can be read and |
---|
707 | displayed by TreeTool, TreeView and Phylowin. An option is available to |
---|
708 | correctly place the bootstrap values on the branches with which they are |
---|
709 | associated. |
---|
710 | |
---|