library_construction_protocol: Embryos were dissociated in 460ul of .25% trypsin and 40ul 100mg/ml collagenase I. Cells were filtered using a 40uM cell strainer. Cell concentratoins were quantified with the TC20 Automated Cell Counter then diluted to 800 cells/ul in .04%. The University of Oregon Genomics and Cell Characterization Core prepared single cell libraries for the two samples using the 10X Genomics Single Cell 3' Genome Expression mRNAseq kit with NextGEM v3.1 chemistry. 10X Genomics Single Cell 3' Genome Expression mRNAseq kit with NextGEM v3.1 chemistry