5 * Created by Pat Schloss on 12/17/08.
6 * Copyright 2008 Patrick D. Schloss. All rights reserved.
8 * This is my implementation of the NAST (nearest alignment space termination) algorithm as described in:
10 * DeSantis TZ, Hugenholtz P, Keller K, Brodie EL, Larsen N, Piceno YM, Phan R, & Anderson GL. 2006. NAST: a multiple
11 * sequence alignment server for comparative analysis of 16S rRNA genes. Nucleic Acids Research. 34:W394-9.
13 * To construct an object one needs to provide a method of getting a pairwise alignment (alignment) and the template
14 * and candidate sequence that are to be aligned to each other.
18 #include "sequence.hpp"
19 #include "alignment.hpp"
22 /**************************************************************************************************/
24 Nast::Nast(Alignment* method, Sequence* cand, Sequence* temp) : alignment(method), candidateSeq(cand), templateSeq(temp) {
27 pairwiseAlignSeqs(); // This is part A in Fig. 2 of DeSantis et al.
28 regapSequences(); // This is parts B-F in Fig. 2 of DeSantis et al.
32 errorOut(e, "Nast", "Nast");
38 /**************************************************************************************************/
40 void Nast::pairwiseAlignSeqs(){ // Here we call one of the pairwise alignment methods to align our unaligned candidate
41 // and template sequences
44 alignment->align(candidateSeq->getUnaligned(), templateSeq->getUnaligned());
46 string candAln = alignment->getSeqAAln();
47 string tempAln = alignment->getSeqBAln();
51 candidateSeq->setPairwise("");
52 templateSeq->setPairwise(templateSeq->getUnaligned());
56 if(tempAln[0] == '-'){
57 int pairwiseAlignmentLength = tempAln.length(); // we need to make sure that the candidate sequence alignment
58 for(int i=0;i<pairwiseAlignmentLength;i++){ // starts where the template sequence alignment starts, if it
59 if(isalpha(tempAln[i])){ // starts early, we nuke the beginning of the candidate
60 candAln = candAln.substr(i); // sequence
61 tempAln = tempAln.substr(i);
66 int pairwiseAlignmentLength = tempAln.length();
67 if(tempAln[pairwiseAlignmentLength-1] == '-'){ // we need to make sure that the candidate sequence alignment
68 for(int i=pairwiseAlignmentLength-1; i>=0; i--){// ends where the template sequence alignment ends, if it runs
69 if(isalpha(tempAln[i])){ // long, we nuke the end of the candidate sequence
70 candAln = candAln.substr(0,i+1);
71 tempAln = tempAln.substr(0,i+1);
79 candidateSeq->setPairwise(candAln); // set the pairwise sequences in the Sequence objects for
80 templateSeq->setPairwise(tempAln); // the candidate and template sequences
84 errorOut(e, "Nast", "pairwiseAlignSeqs");
89 /**************************************************************************************************/
91 void Nast::removeExtraGaps(string& candAln, string tempAln, string newTemplateAlign){
93 // here we do steps C-F of Fig. 2 from DeSantis et al.
96 int longAlignmentLength = newTemplateAlign.length();
98 for(int i=0; i<longAlignmentLength; i++){ // use the long alignment as the standard
99 int rightIndex, rightRoom, leftIndex, leftRoom;
101 // Part C of Fig. 2 from DeSantis et al.
102 if((isalpha(newTemplateAlign[i]) != isalpha(tempAln[i]))){ //if there is a discrepancy between the regapped
104 rightRoom = 0; leftRoom = 0;
106 // Part D of Fig. 2 from DeSantis et al. // template sequence and the official template sequence
107 for(leftIndex=i-1;leftIndex>0;leftIndex--){ // then we've got problems...
108 if(!isalpha(candAln[leftIndex])){
109 leftRoom = 1; //count how far it is to the nearest gap on the LEFT side of the anomaly
110 while(leftIndex-leftRoom>=0 && !isalpha(candAln[leftIndex-leftRoom])) { leftRoom++; }
115 for(rightIndex=i+1;rightIndex<longAlignmentLength-1;rightIndex++){
116 if(!isalpha(candAln[rightIndex])){
117 rightRoom = 1; //count how far it is to the nearest gap on the RIGHT side of the anomaly
118 while(rightIndex+rightRoom<longAlignmentLength && !isalpha(candAln[rightIndex+rightRoom])) { rightRoom++; }
123 int insertLength = 0; // figure out how long the anomaly is
124 while(!isalpha(newTemplateAlign[i + insertLength])) { insertLength++; }
125 if(insertLength > maxInsertLength){ maxInsertLength = insertLength; }
127 if((leftRoom + rightRoom) >= insertLength){
129 // Parts D & E from Fig. 2 of DeSantis et al.
130 if((i-leftIndex) <= (rightIndex-i)){ // the left gap is closer - > move stuff left there's
132 if(leftRoom >= insertLength){ // enough room to the left to move
134 string leftTemplateString = newTemplateAlign.substr(0,i);
135 string rightTemplateString = newTemplateAlign.substr(i+insertLength);
136 newTemplateAlign = leftTemplateString + rightTemplateString;
137 longAlignmentLength = newTemplateAlign.length();
139 string leftCandidateString = candAln.substr(0,leftIndex-insertLength+1);
140 string rightCandidateString = candAln.substr(leftIndex+1);
141 candAln = leftCandidateString + rightCandidateString;
144 else{ // not enough room to the left, have to steal some space to
145 string leftTemplateString = newTemplateAlign.substr(0,i); // the right
146 string rightTemplateString = newTemplateAlign.substr(i+insertLength);
147 newTemplateAlign = leftTemplateString + rightTemplateString;
148 longAlignmentLength = newTemplateAlign.length();
150 string leftCandidateString = candAln.substr(0,leftIndex-leftRoom+1);
151 string insertString = candAln.substr(leftIndex+1,rightIndex-leftIndex-1);
152 string rightCandidateString = candAln.substr(rightIndex+(insertLength-leftRoom));
153 candAln = leftCandidateString + insertString + rightCandidateString;
157 else{ // the right gap is closer - > move stuff right there's
158 if(rightRoom >= insertLength){ // enough room to the right to move
160 string leftTemplateString = newTemplateAlign.substr(0,i);
161 string rightTemplateString = newTemplateAlign.substr(i+insertLength);
162 newTemplateAlign = leftTemplateString + rightTemplateString;
163 longAlignmentLength = newTemplateAlign.length();
165 string leftCandidateString = candAln.substr(0,rightIndex);
166 string rightCandidateString = candAln.substr(rightIndex+insertLength);
167 candAln = leftCandidateString + rightCandidateString;
170 else{ // not enough room to the right, have to steal some
171 // space to the left lets move left and then right...
172 string leftTemplateString = newTemplateAlign.substr(0,i);
173 string rightTemplateString = newTemplateAlign.substr(i+insertLength);
174 newTemplateAlign = leftTemplateString + rightTemplateString;
175 longAlignmentLength = newTemplateAlign.length();
177 string leftCandidateString = candAln.substr(0,leftIndex-(insertLength-rightRoom)+1);
178 string insertString = candAln.substr(leftIndex+1,rightIndex-leftIndex-1);
179 string rightCandidateString = candAln.substr(rightIndex+rightRoom);
180 candAln = leftCandidateString + insertString + rightCandidateString;
186 // there could be a case where there isn't enough room in
187 string leftTemplateString = newTemplateAlign.substr(0,i); // either direction to move stuff
188 string rightTemplateString = newTemplateAlign.substr(i+leftRoom+rightRoom);
189 newTemplateAlign = leftTemplateString + rightTemplateString;
190 longAlignmentLength = newTemplateAlign.length();
192 string leftCandidateString = candAln.substr(0,leftIndex-leftRoom+1);
193 string insertString = candAln.substr(leftIndex+1,rightIndex-leftIndex-1);
194 string rightCandidateString = candAln.substr(rightIndex+rightRoom);
195 candAln = leftCandidateString + insertString + rightCandidateString;
203 catch(exception& e) {
204 errorOut(e, "Nast", "removeExtraGaps");
209 /**************************************************************************************************/
211 void Nast::regapSequences(){ //This is essentially part B in Fig 2. of DeSantis et al.
214 string candPair = candidateSeq->getPairwise();
217 string tempPair = templateSeq->getPairwise();
218 string tempAln = templateSeq->getAligned(); // we use the template aligned sequence as our guide
220 int pairwiseLength = candPair.length();
221 int fullAlignLength = tempAln.length();
224 for(int i=0;i<fullAlignLength;i++) { candAln += '.'; }
225 candidateSeq->setAligned(candAln);
229 int fullAlignIndex = 0;
230 int pairwiseAlignIndex = 0;
231 string newTemplateAlign = ""; // this is going to be messy so we want a temporary template
233 while(tempAln[fullAlignIndex] == '.' || tempAln[fullAlignIndex] == '-'){
234 candAln += '.'; // add the initial '-' and '.' to the candidate and template
235 newTemplateAlign += tempAln[fullAlignIndex];// pairwise sequences
239 string lastLoop = "";
241 while(pairwiseAlignIndex<pairwiseLength){
242 if(isalpha(tempPair[pairwiseAlignIndex]) && isalpha(tempAln[fullAlignIndex])
243 && isalpha(candPair[pairwiseAlignIndex])){
244 // the template and candidate pairwise and template aligned have characters
245 // need to add character onto the candidatSeq.aligned sequence
247 candAln += candPair[pairwiseAlignIndex];
248 newTemplateAlign += tempPair[pairwiseAlignIndex];//
250 pairwiseAlignIndex++;
253 else if(isalpha(tempPair[pairwiseAlignIndex]) && !isalpha(tempAln[fullAlignIndex])
254 && isalpha(candPair[pairwiseAlignIndex])){
255 // the template pairwise and candidate pairwise are characters and the template aligned is a gap
256 // need to insert gaps into the candidateSeq.aligned sequence
259 newTemplateAlign += '-';//
262 else if(!isalpha(tempPair[pairwiseAlignIndex]) && isalpha(tempAln[fullAlignIndex])
263 && isalpha(candPair[pairwiseAlignIndex])){
264 // the template pairwise is a gap and the template aligned and pairwise sequences have characters
265 // this is the alpha scenario. add character to the candidateSeq.aligned sequence without progressing
266 // further through the tempAln sequence.
268 candAln += candPair[pairwiseAlignIndex];
269 newTemplateAlign += '-';//
270 pairwiseAlignIndex++;
272 else if(isalpha(tempPair[pairwiseAlignIndex]) && isalpha(tempAln[fullAlignIndex])
273 && !isalpha(candPair[pairwiseAlignIndex])){
274 // the template pairwise and full alignment are characters and the candidate sequence has a gap
275 // should not be a big deal, just add the gap position to the candidateSeq.aligned sequence;
277 candAln += candPair[pairwiseAlignIndex];
278 newTemplateAlign += tempAln[fullAlignIndex];//
280 pairwiseAlignIndex++;
282 else if(!isalpha(tempPair[pairwiseAlignIndex]) && !isalpha(tempAln[fullAlignIndex])
283 && isalpha(candPair[pairwiseAlignIndex])){
284 // the template pairwise and aligned are gaps while the candidate pairwise has a character
285 // this would be an insertion, go ahead and add the character->seems to be the opposite of the alpha scenario
287 candAln += candPair[pairwiseAlignIndex];
288 newTemplateAlign += tempAln[fullAlignIndex];//
289 pairwiseAlignIndex++;
292 else if(isalpha(tempPair[pairwiseAlignIndex]) && !isalpha(tempAln[fullAlignIndex])
293 && !isalpha(candPair[pairwiseAlignIndex])){
294 // template pairwise has a character, but its full aligned sequence and candidate sequence have gaps
295 // this would happen like we need to add a gap. basically the opposite of the alpha situation
297 newTemplateAlign += tempAln[fullAlignIndex];//
301 else if(!isalpha(tempPair[pairwiseAlignIndex]) && isalpha(tempAln[fullAlignIndex])
302 && !isalpha(candPair[pairwiseAlignIndex])){
303 // template and candidate pairwise are gaps and the template aligned is not a gap this should not be possible
304 // would skip the gaps and not progress through full alignment sequence
307 mothurOut("We're into D " + toString(fullAlignIndex) + " " + toString(pairwiseAlignIndex)); mothurOutEndLine();
308 pairwiseAlignIndex++;
311 // everything has a gap - not possible
314 mothurOut("We're into F " + toString(fullAlignIndex) + " " + toString(pairwiseAlignIndex)); mothurOutEndLine();
315 pairwiseAlignIndex++;
320 for(int i=fullAlignIndex;i<fullAlignLength;i++){
322 newTemplateAlign += tempAln[i];//
326 for(int i=0;i<candAln.length();i++){
327 if(candAln[i] == 'Z' || !isalnum(candAln[i])) { candAln[i] = '.'; } // if we padded the alignemnt from
328 else{ start = i; break; } // blast with Z's, change them to
331 for(int i=candAln.length()-1;i>=0;i--){ // ditto.
332 if(candAln[i] == 'Z' || !isalnum(candAln[i])) { candAln[i] = '.'; }
333 else{ end = i; break; }
336 for(int i=start;i<=end;i++){ // go through the candidate alignment sequence and make sure that
337 candAln[i] = toupper(candAln[i]); // everything is upper case
341 if(candAln.length() != tempAln.length()){ // if the regapped candidate sequence is longer than the official
342 removeExtraGaps(candAln, tempAln, newTemplateAlign);// template alignment then we need to do steps C-F in Fig.
343 } // 2 of Desantis et al.
346 candidateSeq->setAligned(candAln);
348 catch(exception& e) {
349 errorOut(e, "Nast", "regapSequences");
354 /**************************************************************************************************/
356 float Nast::getSimilarityScore(){
359 string cand = candidateSeq->getAligned();
360 string temp = templateSeq->getAligned();
361 int alignmentLength = temp.length();
365 for(int i=0;i<alignmentLength;i++){
366 if(cand[i] == '-' && temp[i] == '-'){
369 else if(cand[i] != '.' && temp[i] != '.'){
372 if(cand[i] != temp[i]){
377 float similarity = 100 * (1. - mismatch / (float)denominator);
378 if(denominator == 0){ similarity = 0.0000; }
383 catch(exception& e) {
384 errorOut(e, "Nast", "getSimilarityScore");
389 /**************************************************************************************************/
391 int Nast::getMaxInsertLength(){
393 return maxInsertLength;
397 /**************************************************************************************************/