Stranded TruSeq mRNAseq Illumina : Sequencing libraries were generated from 1 μg of RNA samples with the TruSeq mRNA kit v.2 (Illumina). Size and concentration of sequencing libraries were determined with DNA-chip (Bioanalyser 2100, Agilent) and the concentrations adjusted to 7 pM. Multiplexed samples were loaded on a total number of three sequencing lanes. Paired end reads (2 × 50 nucleotides) were obtained on a Hiseq1000 using SBS v3 kits (Illumina).