Extended Data Figure 4: Schematic of the IMPC embryonic lethal phenotyping pipeline.

Lines were defined as lethal if zero homozygous animals were identified after ≥ 28 animals had been genotyped. The KOMP2/IMPC centres began with a mid-gestation (E12.5) screen, while the DMDD program initiated screening at the organogenesis phase (E14.5). If no homozygotes were identified (after ≥ 28 embryos screened), centres examined and characterized embryos at the pattern formation stage (E9.5). Homozygous embryos at this stage were scored for gross anatomical defects and imaged using OPT. If live homozygotes were identified at E12.5, centres proceeded with the screen at E15.5 or E18.5. This decision was based on the presence of any observable phenotype at E12.5 and was at the discretion of the centre. Embryos collected at E15.5 were imaged via iodine-contrast microCT. Once sufficient numbers were collected, image registration and quantitative volumetric analysis was performed. Each time point should be considered independently, as some included strains have not been completely analysed and progression through each time point is at the discretion of the centre. For each term, two mutants with the same phenotype were required to score a hit.