Day 7 BL
Cell lysis buffer was used to collect embryos (10-15 expanded-stage embryos per pool) for RNA sequencing. Three micrograms of RNA, isolated using Triazol Reagent (Invitrogen Life Technologies), were used for RNA sample preparation. Sequencing libraries were generated from mRNA purified from total RNA using the Illumina HiSeq platform. cDNA fragments of 400-500 bp were selected, and fragments with ligated adapters at both ends were enriched using the Illumina PCR Primer Cocktail. The products were purified using the AMPure XP system and quantified using the Agilent high-sensitivity DNA assay on a Bioanalyzer 2100 system (Agilent). The sequencing library was subsequently sequenced on the NovaSeq 6000 platform (Illumina) by Shanghai Personal Biotechnology Co. Ltd.