Samples were collected from healthy, unrelated research volunteers via the NIHR Cambridge BioResource (Methods). We established 711 lines from 301 donors (>1 line for 82% of donors, >2 lines for 50%), which were profiled using an initial set of ‘Tier 1‘ assays (Fig. 1a). These included array-based genotyping and gene expression profiling of the iPSCs and their fibroblast progenitors, as well as an assessment of the pluripotency and differentiation properties of the iPSCs. Using immunohistochemistry followed by quantitative image analysis (hereafter ‘Cellomics’), we measured protein expression of pluripotency markers in 307 lines and differentiated 372 lines into neuroectoderm, mesoderm, and endoderm8 measuring expression of three lineage-specific markers in each germ layer (Fig. 1a; Extended Data Fig. 1). We then selected 1-2 lines per donor to minimise the number of genetic abnormalities and performed further phenotyping (hereafter ‘Tier 2’) using RNA-seq, DNA methylation arrays, quantitative proteomics and cell morphological imaging in 239, 27, 16 and 24 lines, respectively (Supplementary Table 1).
