Want to use extract_genomic_dna in command line

[louis7781x]

bx-python is a library for manipulating biological data.

bx.seq.nib handles DNA sequences, packing the file as 4 bits per character.

twobit is a patch which uses the 2 bit datatype instead, as mentioned on the galaxy dev discussions.

If you want to run the script, you have to install the bx-python library, using these instructions.

Thanks a lot!

I will install bx-python and try the script again.

[Blahah404]

bx-python is a library for manipulating biological data.

bx.seq.nib handles DNA sequences, packing the file as 4 bits per character.

twobit is a patch which uses the 2 bit datatype instead, as mentioned on the galaxy dev discussions.

If you want to run the script, you have to install the bx-python library, using these instructions.

[louis7781x]

Hi everyone ,I want to use command line to run extract_genomic_dna.py from tool of galaxy.

Here is code of extract_genomic_dna.py.

In the beginning,need to import some module.

import sys, string, os, re
from bx.cookbook import doc_optparse
import bx.seq.nib
import bx.seq.twobit

Does anyone know what is bx.seq.nib and bx.seq.twobit?

Both it are also python code?

I know doc_optparse which is python code [link-->https://bitbucket.org/ajish/bx-omelo...ib/bx/cookbook]

#!/usr/bin/env python
"""
usage: %prog $input $out_file1
-1, --cols=N,N,N,N: Columns for start, end, strand in input file
-o, --output_format=N: the data type of the output file
-s, --seq_path=N: the directory containing the chromosome fasta files
-l, --left_flank=N: extra bases on the left
-r, --right_flank=N: extra bases on the right
"""
import sys, string, os, re
from bx.cookbook import doc_optparse
import bx.seq.nib
import bx.seq.twobit

assert sys.version_info[:2] >= ( 2, 4 )

def stop_err( msg ):
sys.stderr.write( msg )
sys.exit()

# Default chrom, start, end, strand cols for a bed file
BED_DEFAULT_COLS = 0, 1, 2, 5

def parse_cols_arg( cols ):
"""Parse a columns command line argument into a four-tuple"""
if cols:
# Handle case where no strand column included - in this case, cols
# looks something like 1,2,3,
if cols.endswith( ',' ):
cols += '0'
col_list = map( lambda x: int( x ) - 1, cols.split(",") )
return col_list
else:
return BED_DEFAULT_COLS

def reverse_complement( s ):
complement_dna = {"A":"T", "T":"A", "C":"G", "G":"C", "a":"t", "t":"a", "c":"g", "g":"c", "N":"N", "n":"n" }
reversed_s = []
for i in s:
reversed_s.append( complement_dna[i] )
reversed_s.reverse()
return "".join( reversed_s )

def __main__():

lflank = 0
rflank = 0

options, args = doc_optparse.parse( __doc__ )
try:
chrom_col, start_col, end_col, strand_col = parse_cols_arg( options.cols )
output_format = options.output_format
seq_path = options.seq_path
if ( options.left_flank): lflank = int(options.left_flank)
if ( options.right_flank): rflank = int( options.right_flank)
input_filename, output_filename = args
except:
doc_optparse.exception()
includes_strand_col = strand_col >= 0
strand = None
nibs = {}
twobits = {}
if not os.path.exists( seq_path ):
# If this occurs, we need to fix the metadata validator.
print "No sequences are available for '%s', request them by reporting this error."

skipped_lines = 0
first_invalid_line = 0
invalid_line = ''
fout = open( output_filename, "w" )
warnings = []
warning = ''
twobitfile = None
dbkey=seq_path

for i, line in enumerate( open( input_filename ) ):
line = line.rstrip( '\r\n' )
if line and not line.startswith( "#" ):
fields = line.split( '\t' )
try:
chrom = fields[chrom_col]
ostart = int( fields[start_col] )
oend = int( fields[end_col] )
start = ostart - lflank
end = oend + rflank
if includes_strand_col:
strand = fields[strand_col]
except:
warning = "Invalid chrom, start or end column values. "
warnings.append( warning )
skipped_lines += 1
if not invalid_line:
first_invalid_line = i + 1
invalid_line = line
continue
if start > end:
warning = "Invalid interval, start '%d' > end '%d'. " % ( start, end )
warnings.append( warning )
skipped_lines += 1
if not invalid_line:
first_invalid_line = i + 1
invalid_line = line
continue

if strand not in ['+', '-']:
strand = '+'
sequence = ''

if seq_path and os.path.exists( "%s/%s.nib" % ( seq_path, chrom ) ):
if chrom in nibs:
nib = nibs[chrom]
else:
nibs[chrom] = nib = bx.seq.nib.NibFile( file( "%s/%s.nib" % ( seq_path, chrom ) ) )
try:
sequence = nib.get( start, end-start )
except:
warning = "Unable to fetch the sequence from '%d' to '%d' for build '%s'. " %( start, end-start, dbkey )
warnings.append( warning )
skipped_lines += 1
if not invalid_line:
first_invalid_line = i + 1
invalid_line = line
continue
elif seq_path and os.path.isfile( seq_path ):
if not(twobitfile):
twobitfile = bx.seq.twobit.TwoBitFile( file( seq_path ) )
try:
sequence = twobitfile[chrom][start:end]
except:
warning = "Unable to fetch the sequence from '%d' to '%d' for build '%s'. " %( start, end-start, dbkey )
warnings.append( warning )
skipped_lines += 1
if not invalid_line:
first_invalid_line = i + 1
invalid_line = line
continue
else:
warning = "Chromosome by name '%s' was not found for build '%s'. " % ( chrom, dbkey )
warnings.append( warning )
skipped_lines += 1
if not invalid_line:
first_invalid_line = i + 1
invalid_line = line
continue
if sequence == '':
warning = "Chrom: '%s', start: '%s', end: '%s' is either invalid or not present in build '%s'. " %( chrom, start, end, dbkey )
warnings.append( warning )
skipped_lines += 1
if not invalid_line:
first_invalid_line = i + 1
invalid_line = line
continue
if includes_strand_col and strand == "-":
sequence = reverse_complement( sequence )
sequence = sequence[0:lflank].lower() + sequence[lflank:len(sequence)-rflank+1].upper() + sequence[len(sequence)-rflank+1:len(sequence)].lower()

if output_format == "fasta" :
l = len( sequence )
c = 0
fields = [dbkey, str( chrom ), str( ostart ), str( oend ), strand]
meta_data = "_".join( fields )
fout.write( ">%s\n" % meta_data )
while c < l:
b = min( c + 50, l )
fout.write( "%s\n" % str( sequence[c:b] ) )
c = b
else: # output_format == "interval"
meta_data = "\t".join( fields )
fout.write( "%s\t%s\n" % ( meta_data, str( sequence ) ) )

fout.close()

if warnings:
warn_msg = "%d warnings, 1st is: " % len( warnings )
warn_msg += warnings[0]
print warn_msg
if skipped_lines:
print 'Skipped %d invalid lines, 1st is #%d, "%s"' % ( skipped_lines, first_invalid_line, invalid_line )

if __name__ == "__main__": __main__()