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Using subtractbed(bedtools) to create intron gff

Hi all,

I have to extract intronic sequences from gff file (species - buffalo) to create training data set for CPAT. I am trying to do it with betools. Can anyone please tell me whether the following procedure is correct?

(ucsc table browser doesnot have sequences for buffalo, perl exttract_seq_from_gff3.pl -d genome.fa - gene_intron.gff3 > output_intron.fa from link also didnot work)

awk -F'\t' $3=='gene' my_gff >gene_gff

awk -F'\t' $3=='exons' my_gff >exon_gff`

subtractBed -a gene_gff -b exon_gff >intron_gff

fastaFromBed -fi genome.fa -bed intron.gff -fo intron.fa

Is there anyway to check if the regions in resultant intron gff/fa file is actually introns.

Please give me suggestions. Thanks in advance!

rna-seq

if you can get hold of the actual fasta sequence of those 'intron's you can check whether they all (or the vast majority) start with GT/GC and end in AG dinucleotide . This will give you a hint but is certainly not a bulletproof approach

Hello drkousi31!

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In short, intron is the complement of intergenic and exonic regions. For a step-by-step tutorial, see: A: how to get intronic and intergenic sequences based on gff file?

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