library_construction_protocol: Total RNA was extracted from hearts using Trizol according to the manufacture's protocol. 1. Poly-A mRNA capture and reverse transcription for cDNA synthesis: oligo-dT primer to capture just the mRNA (contains sample barcode, UMI, and Read 1 sequences).2. Second strand synthesis and tagmentation: double stranded-cDNA is generated. Tagmentation creates fragments and incorporates Read 2 sequence. 3. Illumina library amplification: adds unique dual indices (UDI = i5, i7) and P5/P7 sequences.