1 | #Please insert up references in the next lines (line starts with keyword UP) |
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2 | UP arb.hlp |
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3 | UP glossary.hlp |
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4 | UP pt_server.hlp |
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5 | |
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6 | #Please insert subtopic references (line starts with keyword SUB) |
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7 | |
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8 | # Hypertext links in helptext can be added like this: LINK{ref.hlp|http://add|bla@domain} |
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9 | |
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10 | #************* Title of helpfile !! and start of real helpfile strunk ******** |
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11 | TITLE Probe Collection Matching |
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12 | |
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13 | OCCURRENCE ARB_NT/Probes/Match Probes with Specificity |
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14 | |
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15 | |
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16 | DESCRIPTION |
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17 | |
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18 | Searches for potential probe target sites within the sequence |
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19 | entries of the corresponding 'PT_SERVER' (not the current) |
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20 | database from a list of named probes in a probe collection. Matching |
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21 | is performed with the maximum allowable number of mismatches for |
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22 | each given probe. |
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23 | |
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24 | Probe collections are created or loaded with the PROBE COLLECTION |
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25 | window. Probes must be named with unique names otherwise the |
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26 | match results cannot be reconcilled correctly. Similarly, species |
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27 | within the tree must also have unique names for the match processing |
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28 | to work correctly. |
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29 | |
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30 | To add a probe to the collection enter the 'Target String' and the |
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31 | 'Probe Name' and press the ADD button. To remove a probe from the |
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32 | collection select the probe from the 'Probes' list and press the |
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33 | REMOVE button. Pressing the 'FORGET' button will remove all probes |
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34 | from the collection and start a fresh. |
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35 | |
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36 | To save the probe collection to file press the 'SAVE' button and |
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37 | to load a previously created collection press the 'LOAD' button. |
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38 | Probe collections are stored in a simple XML format so they can |
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39 | be easily created with an external text editor. The file format |
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40 | is detailed below. |
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41 | |
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42 | The 'Match Weighting' matrix specifies how mismatch penalities will |
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43 | be alloted to sequence mismatches. The 'Positional Weighting' |
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44 | parameters adjust the mismatch penalities according to position |
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45 | through the following equations: |
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46 | |
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47 | S = -ln(10) / 'Width' |
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48 | |
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49 | P = (((2.0 * 'position') - 'length') / 'length') - 'Bias' |
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50 | |
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51 | Weight = exp(S * P * P) |
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52 | |
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53 | where 'position' is the sequence position and 'length' is the probe |
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54 | length. weighting function gives a bell curve shape whose spread |
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55 | is controlled by the 'Width' parameter, centre is controlled |
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56 | by the 'Bias' parameter and whose maximum is one. |
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57 | |
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58 | For the default values of 1 and 0 for 'Width' and 'Bias' respectively |
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59 | the weighting function has a value of 1 for a position that is half |
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60 | the probe length and 0.1 at the zeroth position and the probe length |
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61 | position. |
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62 | |
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63 | The 'Match Weighting' and 'Positional Weighting' parameters are |
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64 | saved as part of the probe collection XML file. |
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65 | |
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66 | The MATCH PROBES WITH SPECIFICITY window is used to perform probe |
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67 | collection matching. The 'Probes' list shows the probes in the |
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68 | probe collection to be matched. If the list is empty you can click |
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69 | on the EDIT button to open the PROBE COLLECTION window and create |
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70 | or open a probe collection. The CLEAR button clears any previous |
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71 | match results but leaves the probe collection in tact. |
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72 | |
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73 | You need to select a 'PT_SERVER' from the menu displayed after |
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74 | pressing the 'PT_SERVER' button before you can carry out a probe |
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75 | collection match. Press the MATCH button to carry out the match |
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76 | operation. When the match is complete the number of matches found |
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77 | will be displayed and the complete list of match results can be |
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78 | viewed by pressing the RESULTS button. Be warned that with large |
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79 | probe collections this can be a very large text file. |
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80 | |
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81 | Match results are displayed in the DENDROGRAM view using a series |
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82 | of vertical bars (one bar per probe) on the left hand side indicating |
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83 | regions in the tree where matches occur. Left mouse clicking on the |
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84 | bar will open a status message telling you which probe the bar |
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85 | corresponds to. |
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86 | |
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87 | SECTION Match display control |
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88 | |
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89 | What constitutes a match is controlled by the MATCH DISPLAY CONTROL |
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90 | parameters in the MATCH DISPLAY CONTROL window. The controls |
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91 | allow you to test, in real time, the match performance of probe |
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92 | collections without having to re-run the time consuming match operation. |
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93 | |
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94 | The 'Mismatch threshold' slider controls the threshold level that |
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95 | dictates whether a partial match will be regarded as a match or a |
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96 | mismatch. The scale of the 'Mismatch threshold' spans the range |
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97 | from zero to the maximum match weight for the found match results. |
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98 | |
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99 | The 'Clade marked threshold' slider controls the threshold level |
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100 | (between 0 and 100%) that governs whether a clade is marked as |
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101 | matched. For example, if the slider was set to 70% it would indicate |
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102 | that at least 70% of species within a clade must match to the degree |
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103 | dictated by the 'Mismatch threshold' before the clade is marked as |
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104 | matched. |
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105 | |
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106 | In a similar manner, the 'Clade partially marked threshold' slider |
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107 | controls the threshold level (between 0 and 100%) that governs whether |
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108 | a clade is marked as partially matched. Partial clade matches are |
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109 | indicated with a stippled bar whereas for a full match the bar is |
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110 | solid. |
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111 | |
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112 | More options are available via 'Marker display settings' |
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113 | (see LINK{nt_tree_marker_settings.hlp}). |
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114 | |
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115 | SECTION Display interaction |
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116 | |
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117 | Click (and drag) on a marker shown in tree display, to |
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118 | display its name and to select the corresponding probe |
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119 | in the probe selection list. |
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120 | |
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121 | SECTION PROBE COLLECTION XML |
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122 | |
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123 | <?xml version="1.0" encoding="UTF-8" standalone="no"?> |
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124 | <!DOCTYPE probe_collection> |
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125 | <probe_collection name=""> |
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126 | <probe_list> |
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127 | <probe seq="AGGUCACACCCGUUCCCA" name="probe1"/> |
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128 | <probe seq="AGGUCACACCCGUUCCCG" name="probe2"/> |
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129 | <probe seq="AGGUCACACCCGUUCCCT" name="probe3"/> |
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130 | . |
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131 | . |
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132 | . |
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133 | </probe_list> |
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134 | <match_weighting width="1" bias="0"> |
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135 | <penalty_matrix values="0 1 1 2 1 0 1 1 1 1 0 1 2 1 1 0"/> |
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136 | </match_weighting> |
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137 | </probe_collection> |
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138 | |
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139 | |
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140 | The penalty matrix values follow row major ordering. |
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141 | |
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142 | NOTES |
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143 | |
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144 | The 'PT_SERVER' database ('*.arb' and '*.arb.pt') stored in |
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145 | '$ARBHOME/lib/pts' is used for probe target searching not the |
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146 | current database. |
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147 | |
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148 | The 'PT_SERVER' database has to be updated ('ARB_NT/Probes/Probe |
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149 | Admin') if species entries should be considered for probe target |
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150 | searching which have been added or modified (sequence symbols) |
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151 | later than the date of the most recent 'PT_SERVER' database |
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152 | update. |
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153 | |
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154 | Probe target searching does not depend on correctly aligned |
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155 | sequences and is not affected by any modifications of database |
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156 | entries except changes of sequence residues. |
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157 | |
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158 | |
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159 | EXAMPLES |
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160 | |
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161 | None |
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162 | |
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163 | |
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164 | WARNINGS |
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165 | |
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166 | Take care to ensure that all probes in the probe collection and all |
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167 | species in the current database are uniquely named. Not doing so |
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168 | will result in results not being displayed correctly. |
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169 | |
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170 | BUGS |
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171 | |
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172 | No bugs known |
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