Human pluripotent stem cells (hPSCs) may significantly improve drug development pipeline, serving as an in vitro system for the identification of novel leads, and for testing drug toxicity. Furthermore, these cells may be used to address the issue of differential drug response, a phenomenon greatly influenced by genetic factors. This application depends on the availability of hPSC lines from populations with diverse ancestries. So far, it has been reported that most lines of hPSCs derived worldwide are of European or East Asian ancestries. We have established 23 lines of hPSCs from Brazilian individuals, and we report the analysis of their genomic ancestry. We show that embryo-derived PSCs are mostly of European descent, while induced PSCs derived from participants of a national-wide Brazilian cohort study present high levels of admixed European, African and Native American genomic ancestry. Additionally, we use high density SNP data and estimate local ancestries, particularly those of CYP genes loci. Such information will be of key importance when interpreting variation among cell lines with respect to cellular phenotypes of interest. The availability of genetically admixed lines of hPSCs will be of relevance when setting up future in vitro studies of drug response.Human pluripotent stem cells (hPSCs) are an ideal cell source for the development of cell based assays for drug response. In addition to their extensive proliferation and genetic stability in culture, these human cells can give rise to primary cell types relevant for drug response, including cardiomyocytes, hepatocytes and neurons 1 . Individual differences in drug response can result from the effects of age, sex, disease, ancestry, or drug interactions, but genetic factors play a major role in influencing adverse drug reactions and ineffective therapy 2 . Thus, a collection of genetically diverse lines of hPSCs is required for a broader study of differential drug response in vitro 3 .To date, most lines of hPSCs available are of European or Eastern Asian ancestry 4 , although one hiPSC line from a Native American, and one from an African (Yoruba) have been reported 5 . More recently, one hiPSC line of African American and of Hispanic Latino ancestry each have been described, although the authors do not show the genetic evidence of those ethnicities 6 .The Brazilian population results from 500 years of admixture among the original Native Americans, Europeans (mostly Portuguese), and sub-Saharan Africans, most of which were brought to the country as slaves 7 . Different analyses of genomic ancestry in Brazil have shown that, on average, the urban population has 60% contribution from European, 25% from African, and 15% from Native American populations, although these proportions vary according to the Brazilian geographic region analyzed [7][8][9][10][11] . Therefore, from the genetic point of view the Brazilian population is significantly distinct from the ancestral populations, containing novel genotypes and haplotypes that may impact various phenotyp...
