perl脚本从爆破结果中选择最佳的blast基因系

时间：2014-01-08 18:45:49

标签： perl output bioinformatics blast

我有一个带有blast输出的巨大文件，我需要选择查询ID，主题gi和框架（基本上是整行），e值最小，省略重复的行（省略所有其他行与其他更高的e值）。这就是文件的样子：

# BLASTX 2.2.28+
# 0 hits found
# BLASTX 2.2.28+
# Query: Tx6_c1_seq1
# Database: /mnt/swissprot
# Fields: query id, subject gi, subject title, subject length, gap opens, q. start, q. end, s. start, s. end, evalue, % subject coverage, % identity, query/sbjct frames
# 24 hits found
Tx6_c1_seq1 6439823 RecName: Full=E3 ubiquitin-protein ligase siah-1; AltName: Full=Seven in absentia homolog 1 434 1   9   173 224 282 1e-06   65  32.20   3/0
Tx6_c1_seq1 577332  RecName: Full=Putative E3 ubiquitin-protein ligase SINAT1; AltName: Full=Seven in absentia homolog 1    305 1   9   179 111 171 3e-05   67  32.79   3/0
Tx6_c1_seq1 3548505 RecName: Full=E3 ubiquitin-protein ligase siah-1; AltName: Full=Seven in absentia homolog 1 419 2   9   173 209 267 8e-05   65  32.20   3/0
Tx6_c1_seq1 577547  RecName: Full=E3 ubiquitin-protein ligase siah2; AltName: Full=Seven in absentia homolog 2; AltName: Full=Xsiah-2   313 1   15  173 125 181 2e-04   62  29.82   3/0
Tx6_c1_seq1 577417  RecName: Full=E3 ubiquitin-protein ligase Siah1; AltName: Full=Seven in absentia homolog 1; Short=Siah-1    282 1   15  173 96  152 3e-04   62  29.82   3/0
Tx6_c1_seq1 577554  RecName: Full=E3 ubiquitin-protein ligase SINAT2; AltName: Full=Seven in absentia homolog 2 308 1   9   179 114 174 4e-04   67  31.15   3/0
# BLASTX 2.2.28+
# Query: Tx_11_c0_seq1
# Database: /mnt/swissprot
# Fields: query id, subject gi, subject title, subject length, gap opens, q. start, q. end, s. start, s. end, evalue, % subject coverage, % identity, query/sbjct frames
# 1 hits found
Tx_11_c0_seq1   977285  RecName: Full=120.7 kDa protein in NOF-FB transposable element  1056    15  957 28  147 455 8e-13   79  27.81   -2/0
# BLASTX 2.2.28+
# Query: Tx_11_c1_seq1

这种情况下的预期输出应该只是这两行，因为它们是e_value最小的那一行：

Tx6_c1_seq1 6439823 RecName: Full=E3 ubiquitin-protein ligase siah-1; AltName: Full=Seven in absentia homolog 1 434 1   9   173 224 282 1e-06   65  32.20   3/0
Tx_11_c0_seq1   977285  RecName: Full=120.7 kDa protein in NOF-FB transposable element  1056

我写了我的代码，但似乎没有用。你能帮我解决一下这个问题。我非常感谢您的时间和帮助。这就是我到目前为止所做的：

#!/usr/bin/perl -w

# Author:
# 01/07/2014
# This script removes duplicate records from a "short" format BLAST output file, and keeps only the "best" records  (sorts by smallest e-value and then biggest percent identity)
# Usage: bestblast.pl <input file> <output file>

#-----------------------------------------------------------------------------------------------------------------------------------------
#Deal with passed parameters
#-----------------------------------------------------------------------------------------------------------------------------------------
#If no arguments are passed, show usage message and exit program.
if ($#ARGV == -1) {
    usage("BLAST BEST 1.0 2014");
    exit;
}

#get the names of the input file (first argument passed) and output file (second argument passed)
$in_file = $ARGV[0];
$out_file = $ARGV[1];

#Open the input file for reading, open the output file for writing.
#If either are unsuccessful, print an error message and exit program.
unless ( open(IN, "$in_file") ) {
    usage("Got a bad input file: $in_file");
    exit;
}
unless ( open(OUT, ">$out_file") ) {
    usage("Got a bad output file: $out_file");
    exit;
}

#Everything looks good. Print the parameters we've found.
print "Parameters:\ninput file = $in_file\noutput file = $out_file\n\n";

#-----------------------------------------------------------------------------------------------------------------------------------------
#The main event
#-----------------------------------------------------------------------------------------------------------------------------------------

$counter = 0;
$total_counter = 0;

print "De-duplicating File...\n";

@in = <IN>;

#Do stuff for each line of text in the input file.
foreach $line (@in) {
    #if the line starts with a pound symbol, it is not real data, so skip this line.
    if ( $line =~ /^#/ ) {
     next;
     }

    #Count the total number of data lines in the file.
    $total_counter++;

    #The chomp commands removes any new line (and carriage return) characters from the end of the line.
    chomp($line);

    #Split up the tab delimited line, naming only the variables we are interested in (i.e. query id, subject gi, subject title, subject length, gap opens, q. start, q. end, s. start, s. end, evalue, % subject coverage, % identity, query/sbjct frames)
    ($query_id, $subject_gi, $subject_title, $subject_length, $gap_opens, $q_start, $q_end, $s_start, $s_end, $evalue, $subject_coverage, $identity, $query_sbjct_frames) = split(/\t/, $line);

    #check to see if the id label is already in the list of ids (called dedupe)
    #if its not there, add it.
    if ( $dedupe{$query_id} ) {
    #if it is, look at the old line to see if it is still "better" than the new one.
    ($query_id, $subject_gi, $subject_title, $subject_length, $gap_opens, $q_start, $q_end, $s_start, $s_end, $list_evalue, $subject_coverage, $list_identity, $query_sbjct_frames) = split(/\t/,$dedupe{$query_id});

    #if the new evalue is better than the old one, change the value of this id to the new line.
    #otherwise, if the the new evalue is the same, and the percent_identity is better, change the value of this id to the new line.
    #otherwise, don't do anything (keep the old line).
    if ( $evalue < $list_evalue ) {
        $dedupe{$query_id} = $line;
    }
    elsif ( $evalue == $list_evalue ) {
        if ( $identity > $list_identity ) {
        $dedupe{$query_id} = $line;
        }
    }
    }
    else {
    $dedupe{$query_id} = $line;
    #count the number of non-duplicated lines we have.
    $counter++;
    }
}
print "Total # records = $total_counter\nBest only # records = $counter\n";
print "Writing to output file...\n";

#Print the final "dedupe" list to the new file (adding the new line back on the end).
foreach $query_id (sort keys %dedupe) {
    print OUT "$dedupe{$query_id}\n";
}

#Close the files.
close(IN);
close(OUT);
print "Done.\n";

#-----------------------------------------------------------------------------------------------------------------------------------------
#Subroutines
#-----------------------------------------------------------------------------------------------------------------------------------------
sub usage {
    my($message) = @_;
    print "\n$message\n";

    print "\nThis script removes duplicate records from a \"short\" format BLAST output file, and keeps only the \"best\" records.\nIt sorts by smallest e-value and then biggest percent identity.\n";
    print "Usage: bestbenter code herelast.pl <input file> <output file>\n";
    print "\n Author \n";
    print "01/07/2014\n";
}

3 个答案:

答案 0 :(得分：1)

你为什么要编写自己的blast解析器。使用BioPerl

http://www.bioperl.org/wiki/HOWTO:SearchIO#NCBI-BLAST_parsing_problems

我不再使用Perl了，但这里有什么操作的粗略概念

while (my $result = $report->next_result) {
    print "Query: ".$result->query_name."\n";
    while (my $hit = $result->next_hit) {
        while ($hsp = $hit->next_hsp) {
            my evalue = $hsp->evalue;
            #convert to decimal notation
            $decimal_notation = sprintf("%.10g", $scientific_notation);

            ##... i'll leave the rest up to you
        }
     }
}

答案 1 :(得分：0)

尝试在shebang之后在顶部添加“use strict” - 它可能有助于找到其他内容。

尝试将“if（$ dedupe {$ query_id}）”替换为“if（已定义（$ dedupe {$ query_id}））”

请记住，SO上的大多数人都不是生物学家/基因组学家（！）并且不知道你在说什么，我们只看到对我们没有任何意义的数字和单词，所以如果你能更好地解释，我们可能会能够提供更多帮助。

顺便说一句，以下是更惯用的。

next if $line =~ /^#/;

你的代码总是从第64行到第81行。它永远不会进入二级测试 - 它永远不会发现重复。尝试在调试器中运行它，使用：

perl -d yourprog INFILE OUTFILE

然后反复对“下一行”做“n”。您可以使用“p变量名称”打印变量值。

如果我将split（）s的分隔符从制表符更改为空格，我会得到它 - 至少具有正确的输出记录数：

De-duplicating File...
Argument "in" isn't numeric in numeric lt (<) at ./go line 71, <IN> line 21.
Argument "AltName:" isn't numeric in numeric lt (<) at ./go line 71, <IN> line 21.
Argument "homolog" isn't numeric in numeric gt (>) at ./go line 75, <IN> line 21.
Argument "in" isn't numeric in numeric gt (>) at ./go line 75, <IN> line 21.
Argument "in" isn't numeric in numeric lt (<) at ./go line 71, <IN> line 21.
Argument "in" isn't numeric in numeric lt (<) at ./go line 71, <IN> line 21.
Argument "homolog" isn't numeric in numeric gt (>) at ./go line 75, <IN> line 21.
Argument "homolog" isn't numeric in numeric gt (>) at ./go line 75, <IN> line 21.
Argument "in" isn't numeric in numeric lt (<) at ./go line 71, <IN> line 21.
Argument "Full=Seven" isn't numeric in numeric lt (<) at ./go line 71, <IN> line 21.
Argument "homolog" isn't numeric in numeric gt (>) at ./go line 75, <IN> line 21.
Argument "absentia" isn't numeric in numeric gt (>) at ./go line 75, <IN> line 21.
Argument "in" isn't numeric in numeric lt (<) at ./go line 71, <IN> line 21.
Argument "Full=Seven" isn't numeric in numeric lt (<) at ./go line 71, <IN> line 21.
Argument "homolog" isn't numeric in numeric gt (>) at ./go line 75, <IN> line 21.
Argument "absentia" isn't numeric in numeric gt (>) at ./go line 75, <IN> line 21.
Argument "in" isn't numeric in numeric lt (<) at ./go line 71, <IN> line 21.
Argument "Full=Seven" isn't numeric in numeric lt (<) at ./go line 71, <IN> line 21.
Argument "homolog" isn't numeric in numeric gt (>) at ./go line 75, <IN> line 21.
Argument "absentia" isn't numeric in numeric gt (>) at ./go line 75, <IN> line 21.
Total # records = 7
Best only # records = 2
Writing to output file...
Done.
iMac:~/tmp: more out
Tx6_c1_seq1 6439823 RecName: Full=E3 ubiquitin-protein ligase siah-1; AltName: Full=Seven in absentia homolog 1 434 1   9   173 224 282 1e-06   65  32.20   3/0
Tx_11_c0_seq1   977285  RecName: Full=120.7 kDa protein in NOF-FB transposable element  1056    15  957 28  147 455 8e-13   79  27.81   -2/0

答案 2 :(得分：0)

值是用科学记数法表示的，perl会在进行小于比较时将其视为字符串。

我想我也会以不同的方式做重复数据删除...

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