Rafael Sampaio

Dr. Rafael Vilar Sampaio is the Manager of Reproductive Biotechnology at the Reproductive Sciences Department of the Toronto Zoo. He also serves as an Adjunct Professor in the Department of Biomedical Sciences at the Ontario Veterinary College, University of Guelph. He holds a Bachelor's in Biological Sciences and a Master of Science in Cell Biology from the Federal University of Pará in Brazil. His PhD in Sciences was awarded by the University of São Paulo, Brazil, with a cotutelle at the University of Guelph, focusing on epigenetic regulation in bovine nuclear reprogramming. He completed postdoctoral research at the University of California, Davis, studying bovine embryonic stem cell biology and epigenetics, and at the University of Montreal and Boviteq (SEMEX Alliance), working on haploid cell technologies for genomically designed offspring. Before joining the Toronto Zoo, Dr. Sampaio held positions in the biotechnology industry, contributing to reproductive and genomic studies in livestock and wildlife.

Research Interests
Dr. Sampaio's research sits at the intersection of epigenetics, reproductive biotechnology, and conservation science. A central theme of his work is understanding how natural and artificial environments influence epigenetic marks across the genome — from histone modifications to DNA methylation — and how these marks govern early embryo development and nuclear reprogramming. Rooted in reproductive biotechnology and stem cell biology across non-model species, his expertise spans adult, embryonic, and induced pluripotent stem cells, as well as somatic cell nuclear transfer and in vitro embryo production.
His program at the Toronto Zoo and University of Guelph applies this foundation toward a long-term conservation vision: first preserving the genetic diversity of endangered species through biobanking of cells, gametes, and pluripotent stem cells, and then developing the reproductive technologies needed to produce viable primordial germ cells, gametes, and ultimately offspring. To achieve this, his work encompasses interspecific embryo technologies, chimerism, and in vitro gametogenesis, extending platforms developed in livestock models into practical tools for a broad range of endangered species.

Selected Publications

• Bogliotti YS, Wu J, Vilarino M, …, Sampaio RV, …, Ross PJ. Efficient derivation of stable primed pluripotent embryonic stem cells from bovine blastocysts. PNAS. 2018;115(9):2090–2095. doi:10.1073/pnas.1716161115
• Sampaio RV, Sangalli JR, De Bem THC, et al. Catalytic inhibition of H3K9me2 writers disturbs epigenetic marks during bovine nuclear reprogramming. Scientific Reports. 2020;10(1):11493. doi:10.1038/s41598-020-67733-9
• Ross PJ, Sampaio RV. Epigenetic remodeling in preimplantation embryos: cows are not big mice. Animal Reproduction. 2018;15:204–214.
• Sampaio RV, Chiaratti MR, Santos DCN, et al. Generation of bovine (Bos indicus) and buffalo (Bubalus bubalis) adipose tissue-derived stem cells: isolation, characterization, and multipotentiality. Genetics and Molecular Research. 2015;14:53–62.
• Sampaio RV, Conceição SD, Miranda MS, Sampaio LD, Ohashi OM. MT3 melatonin binding site, MT1, and MT2 melatonin receptors are present in oocytes, but only MT1 is present in bovine blastocyst produced in vitro. Reproductive Biology and Endocrinology. 2012;10:103.

Preprints / Under Review

• Brunhara JC, Nogueira CM, Sangalli JR, …, Sampaio RV. Artificial environment impact: O₂ concentration changes between IVM and IVF alter embryo production, metabolism, and epigenetic marks. bioRxiv. 2023. doi:10.1101/2023.11.28.569089
• Chen R, Coquelin ML, Srirattana K, Sampaio RV, …, Abrams ME. Multiplex-edited mice recapitulate woolly mammoth hair phenotypes. bioRxiv. 2025. doi:10.1101/2025.03.03.641227
• Knecht L, Mastracci A, …, Sampaio RV, …, Kehler J. Rapid derivation of cloning-competent cells from peripheral blood advances conservation biobanking. bioRxiv. 2025. doi:10.1101/2025.10.08.680978