library_construction_protocol: Total RNA from individual samples was extracted using the RNeasy mini kit (QIAGEN; 74104). Genomic DNA was digested using DNase I (QIAGEN; 79254) as described in the on-column DNase digestion protocol from QIAGEN. One microgram total RNA was used for library preparation using the TruSeq Stranded mRNA kit (Illumina Inc) following manufacturer's instructions.