Adaptor trimming for TruSeq DNA Methylation

Adaptor trimming for TruSeq DNA Methylation


TruSeq DNA Methylation所使用的adapter序列與 TruSeq Single Index系統相同, bcl2fastq v2.2 guide在拆分過程中該軟體判斷adapter序列的嚴謹度(adapter stringency)定義如下:

The minimum match rate that triggers masking or trimming. This value is calculated as MatchCount / (MatchCount + MismatchCount). … The default value of 0.9 indicates that only reads with > 90% sequence identity with the adapter are trimmed.

(page. 14, bcl2fastq2-v2-20-software-guide)

25 mer 需有 23 mer 符合分析者給予的序列 (92%)
33 mer 需有 30 mer 符合分析者給予的序列 (90.9%)


起初由於TruSeq DNA Methylation的建議讀長較短( 2×75 or 2×100bp),作為因應,提供的trimming序列亦較短;若使用較長的讀長如2×150或以上,亦可以使用33 mer;但整體而言,25 mer就可以達到trim adapter的效果。
Recommended read length: TruSeq DNA Methylation (

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