Rafael Sampaio
BSc, MSc, PhD (Brazil)
Adjunct Professor
Ontario Veterinary College, Department of Biomedical Sciences
Dr. Rafael Vilar Sampaio is the Manager of Reproductive Biotechnology in the Toronto Zoo's Reproductive Sciences Department. 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. He earned his PhD in Sciences from 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 integrates epigenetics, reproductive biotechnology, and conservation science. He studies how natural and artificial environments shape epigenetic marks, from histone modifications to DNA methylation, and how these marks govern early embryo development and nuclear reprogramming. Building on expertise in stem cell biology, somatic cell nuclear transfer, and in vitro embryo production in non-model species, his program at the Toronto Zoo and University of Guelph aims to preserve the genetic diversity of endangered species through biobanking of cells, gametes, and pluripotent stem cells, and to develop interspecific embryo technologies, chimerism, and in vitro gametogenesis to produce gametes and, ultimately, offspring.
Selected Publications
Cruz JB, Nogueira CM, Sangalli JR, …, Sampaio RV. Consistency of oxygen tension during IVM and IVF is critical for epigenetic integrity and redox homeostasis in bovine preimplantation embryos. Theriogenology. 2027;267:118187. doi:10.1016/j.theriogenology.2026.118187
Chen R, Coquelin ML, Srirattana K, Sampaio RV, …, Church GM, Shapiro B, Abrams ME. A multiplex genome editing pipeline for rapid combinatorial trait engineering. Cell Reports Methods. 2026;6:101572. doi:10.1016/j.crmeth.2026.101572
Knecht L, Mastracci A, …, Sampaio RV, …, Shapiro B, Kehler J. Rapid derivation of cloning-competent cells from peripheral blood advances conservation biobanking. Journal of Heredity. 2026;esag048. doi:10.1093/jhered/esag048
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
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
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.
Current Graduate Students & Trainees
Antonella Molinari – Postdoctoral Fellow (incoming, January 2027)
Evelyn Myall – MBS Student
Rhaissa Torres – Visiting International Research Student (Brazil)
Lisa Wilson – MBS Student