Understanding somatic cell characteristics to improve embryo developmental potential in vitro

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After more than 20 years of research, there has been limited progress in the implementation of in vitro embryo technologies for non-domestic species. Insufficient supply of materials for research purposes plays a major role in the slow progress; however, species-specific differences (e.g. seasonality, rates of development) contribute to the challenges of producing offspring. In addition, genetic material currently stored in biobanks around the world consists primarily of frozen sperm. Difficulties in obtaining and cryopreserving oocytes and embryos have limited the proportion of female genetics represented in these biobanks. Our studies in bison (Bison bison) have confirmed the complexities of oocyte handling and culture in this species with low oocyte maturation and in vitro embryo development rates using standard domestic cattle protocols. A recent call to action from the International Union for the Conservation of Nature (IUCN) for the banking of cells from all threatened species to preserve genetic material before it is lost has resulted in an increased interest in somatic cell banking and the initiation of somatic cell banks around the world. One of the primary reasons is the reprogramming capability of somatic cells and their potential use for future offspring production. Our studies have shown that sample collection and culture establishment techniques influenced fibroblast culture characteristics, including chromosome number and telomere length. Furthermore, individual variability in the fibroblast cultures played a significant role in pre-implantation embryo development following somatic cell nuclear transfer (SCNT), although the reason for these differences was not elucidated. In order to improve embryo production using somatic cell-based techniques, such as SCNT, a better understanding of the genetic and epigenetic make-up of the donor cells is necessary to identify, and potentially modify, factors regulating embryo survival. Our research interest lies in understanding the influence of cellular factors on early development of interspecies SCNT embryos to improve its potential use in the production of genetically valuable animals. The proposed research will identify factors in adult somatic cells that may be indicative of SCNT success and examine whether modification of the donor cells can promote proper reprogramming and enhance early embryo viability and quality. In the first phase of the study, characterization of wood bison donor cells will be used to correlate cell parameters with interspecies SCNT success. In the second phase, modification of bison donor cells will be carried out prior to SCNT to evaluate their influence on blastocyst development. This study will increase our understanding of cellular determinants of embryo viability and quality and provide us with potential methods for improving SCNT outcomes in both domestic and non-domestic species.