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Aligner For Allowing Multiple Matches (#N) For A Read

Hi All

Based on your experience could you please recommend an aligner which can accommodate multiple read mapping positions. I have already tried BWA and Mosaik with the option to allow for multiple mappings.

With BWA I dont get the Mapping quality for all mappings and Mosaik gives me low % of reads aligned. I was wondering may be I could try something else.

Thanks! -Abhi

short aligner

Mapping quality can only be calculated for the top hit.

3 answers

try gem-mapper

Hi, recently, I have a problem about GEM. When I want build index for human using GEM, it reported

Creating sequence and location files...
Fatal error: exception
Failure("Command 'echo "-------gem-indexer_fasta2meta+cont" > human_g1k_v37.fasta.log && gem-indexer_fasta2meta+cont -i human_g1k_v37.fasta -c dna --filter-function iupac-dna --strip-unknown-bases-threshold 50 --complement-size-threshold 2000000000 --comp.

The command I used is

./gem-indexer -i /devdata/chhy/masai/bin/human_g1k_v37.fasta -o hum.index -T 4

Could you help me to solve this problem?

Thanks!

You can try the MUMmer suite with the maxmatch option. So allowing multiple matches. Another alternative is to simply use the fast BLAT (not BLAST) aligner.

bowtie does this beautifully.

"With the -k, -a, -m, -M, --best and --strata options, the user can flexibily select which alignments are reported"

http://bowtie-bio.sourceforge.net/manual.shtml#reporting-modes

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