Methylation study

Tuxedo

WD: 63:/data6/chojam96/methylation/tuxedo

Basic Bowtie2 pipeline

Refer to 2108 Hakyung TUXEDO

HTSeq

For detailed information, refer to HTSeq page.

Basic command:

htseq-count -t exon (-f bam) (--stranded=no) (-q) <sorted.bam> <annotation.gff/gtf> > <htseq.txt>

Default input file format is SAM, so specifying '-f bam' for BAM input file is necessary.

For files not following normal HTSeq pipeline, '--stranded=no' option is also required. Refer to 2108 Hakyung TUXEDO.

However, for V. radiata Illumina-sequenced GFF3 files, ID attributes are mixed up, so additional '--idattr' option should be used!

htseq-count -t exon -f bam --stranded=no -q --idattr transcript_id <sorted.bam> <annotation.gff/gtf> > <htseq.txt>

ID attributes may be:

• transcript_id for GTF format
• Name for GFF format
• etc

edgeR

Refer to 2108 Hakyung TUXEDO

If edgeR not installed properly due to some version issues, follow instructions from edgeR installation.

DEG and methylation

DEG

From HTSeq, for six samples (three for K, three for S), files *_htseq.txt were produced and combined into combined_htseq.txt

edgeR was performed on 'combined_htseq.txt' on R studio and 'combined_htseq.count.edgeR' (n=23106) was produced.

DEG was extracted using:

python finddeg.py combined_htseq.count.edgeR combined_htseq.deg

DEGs from each cytosine contexts were extracted using:

python extractmetccount.py <DEG file> <*_genes> <*_count.deg>

CpG_count.deg (n=21)

CHG_count.deg (n=23)

CHH_count.deg (n=4)

Gene methylation count

WD: 63:/data6/chojam96/methylation/expression_methylation

1. From 193:/data2/chojam96/methylation/metilene/metilene_v0.2-7/Vr-Met-S(K), get bismark coverage files

Six files: 'CpG(H)_Vr-Met-S(K)_bismark.cov'

Chr     Pos     Pos     MetPercentage    Met_read    Unmet_read
Vr01    44      44      100     1       0
Vr01    45      45      100     1       0
Vr01    359     359     100     1       0
Vr01    360     360     100     2       0
Vr01    371     371     100     1       0

2. Combine all cytosine context files → 'Vr-Met-S(K)_bismark.cov' and set minimum threshold as (met + unmet) >= 3 → 'Vr-Met-S(K)_bismark.min3.cov'

Chr     Pos     Met_read    Unmet_read
Vr01    417     4       0
Vr01    459     2       1
Vr01    467     1       2
Vr01    606     6       0
Vr01    608     3       1

3. Divide into chromosomes and scaffolds → 'Vr#(scaffold)_S(K).min3.cov'

python dividescaffolds.py Vr-Met-S(K)_bismark.min3.cov

4. Run 'getdata.py': takes GFF - only mRNA - file, complete gene ID and line type (S, K)

Coverage(.cov) files of all the scaffolds should be present in the same working directory!

python getdata.py <GFF.onlymRNA> <Gene ID> <S/K>
python getdata.py ../Vradi_ver6.onlymrna.gff Vradi01g05390.1 S

This produces <Gene ID>_<S/K> file with following format:

'Vradi01g05390.1_S'
Position    Number of counts    Met/Unmet 
#strand:-
8291109 4       met
8291109 -0      unmet
8291141 5       met
8291141 -0      unmet
8291162 4       met
8291162 -2      unmet
8291182 12      met
8291182 -0      unmet