甲基化測序分析流程

1. 對參考基因組和reads進(jìn)行預(yù)處理
   -將C全部替換為T
   -將序列反向互補(bǔ)，G替換為A

2. 將預(yù)處理后的reads比對到參考基因組，比對結(jié)果中序列信息為原始reads（即未進(jìn)行C轉(zhuǎn)T的reads）

3. 甲基化位點(diǎn)
   CpG
   CpHpG
   CHH（H=A,T,G）

4. 甲基化區(qū)域與功能

   • 啟動子區(qū)域 -- 抑制基因表達(dá)
   • 動植物中活躍轉(zhuǎn)錄的基因CpG甲基化程度升高
   • CpHpG通常存在于植物中不表達(dá)的轉(zhuǎn)座子內(nèi)

甲基化測序策略 -- BS-Seq

• WGBS

價格較高，Raw-data 數(shù)據(jù)量龐大，增加分析難度

- RRBS
WGBS的替代方法

This technique combines restriction enzymes and bisulfite sequencing in order to
enrich for the areas of the genome that have a high CpG content. Due to the high cost
and depth of sequencing needed to analyze methylation status in the entire genome,
Meissner et al. developed this technique in 2005 in order to reduce the amount of
nucleotides needed to be sequenced to 1% of the genome.