Homogenization was first performed in TRIzol (Invitrogen #15596026) followed by stepwise phase separation in 1-Bromo-3-chloropropane (Sigma-Aldrich #B9673) and chloroform (Sigma-Aldrich #C2432) before cleanup with RNeasy mini kit columns (Qiagen #74106) and treatment with RNase-free DNase (Qiagen #79254). Libraries were prepared by the NIEHS Epigenomics and DNA Sequencing Core Facility with an Illumina Tru-seq stranded mRNA library prep kit.