# HG changeset patch # User nikhil-joshi # Date 1375845207 14400 # Node ID 8e5357ca8ebdefd45856501dff550468a214efb2 # Parent 6833c884a751f59e76e692b8e3d568d8b6650f82 Uploaded diff -r 6833c884a751 -r 8e5357ca8ebd scythe/scythe.xml --- a/scythe/scythe.xml Tue Aug 06 23:13:08 2013 -0400 +++ b/scythe/scythe.xml Tue Aug 06 23:13:27 2013 -0400 @@ -2,7 +2,17 @@ Trimming adapters/contaminants using a Naive Bayesian classifier - scythe --quiet -a $adapter_file -q $qual_type + scythe --quiet -a $adapter_file + + #if $input_fastq.ext == "fastq": + -q sanger + #else if $input_fastq.ext == "fastqsanger": + -q sanger + #else if $input_fastq.ext == "fastqillumina": + -q illumina + #else if $input_fastq.ext == "fastqsolexa": + -q solexa + #end if #if str($add_tag) == "add_tag_true": -t @@ -16,6 +26,10 @@ -n $min_match #end if + #if str($min_keep) != "": + -M $min_keep + #end if + #if str($matches_file) == "matches_file_true": -m $output_matches #end if @@ -24,27 +38,25 @@ - + - - - - - - - + - + + + + + @@ -61,6 +73,8 @@ Most next generation sequencing reads have deteriorating quality towards the 3'-end. It's common for a quality-based trimmer to be employed before mapping, assemblies, and analysis to remove these poor quality bases. However, quality-based trimming could remove bases that are helpful in identifying (and removing) 3'-end adapter contaminants. Thus, it is recommended you run Scythe before quality-based trimming, as part of a read quality control pipeline. The Bayesian approach Scythe uses compares two likelihood models: the probability of seeing the matches in a sequence given contamination, and not given contamination. Given that the read is contaminated, the probability of seeing a certain number of matches and mistmatches is a function of the quality of the sequence. Given the read is not contaminated (and is thus assumed to be random sequence), the probability of seeing a certain number of matches and mismatches is chance. The posterior is calculated across both these likelihood models, and the class (contaminated or not contaminated) with the maximum posterior probability is the class selected. + +Scythe will infer the quality type from the datatype of the file.