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Find consensus sequence of several DNA sequences

Hi!

I have a list of around 200 different DNA sequences, each ~150 bp long, and I'd like to find a consensus sequence for all of them. I'm sure there is probably a function that does that which I'm not familiar with. Does anyone know which package/function to use to do that? I prefer in python, but R is also OK....

Thanks!

python r alignment consensus sequence
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updated by st.ph.n st.ph.n • written by Bella_p Bella_p

1 answer

You can use Biopython to create a consensus sequence. 

#!/usr/bin/env python

import sys
from Bio import AlignIO
from Bio.Align import AlignInfo

alignment = AlignIO.read(sys.argv[1], 'fasta')
summary_align = AlignInfo.SummaryInfo(alignment)
summary_align.dumb_consensus(float(sys.argv[2]))

Save as consensus.py, run as python consensus.py input.fasta x, where x is the percentage of sequences to call a position in the consensus sequence; i.e. python consensus.py input.fasta 0.5 would mean that a residue or nucleotide would have to be represented in 50% of the sequences to call that position.

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written by st.ph.n st.ph.n

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