Birth of parthenogenetic pigs that grew to adulthood

Parthenogenesis is an asexual reproduction process from an unfertilized egg cell, which naturally occurs in plant, some inveterate animals, and a few vertebrates. In mammals, parthenogenesis cannot naturally produce viable offspring largely due to defective genomic imprinting that arrests embryonic development. Previous studies have demonstrated the feasibility to produce parthenogenetic mice by engineering some imprinted genes, but such an approach has not been successfully applied to other mammals. In this study, using serial somatic cell nuclear transfer (SCNT), we successfully created the first parthenogenetic pig. RNA-Seq and methylation analysis revealed that serial rounds of SCNT recalibrated genome-wide gene expression to a level comparable to those exhibited in normal fertilized embryos. We also identified a suite of master transcriptional factors that may facilitate the genome-wide reprogramming during this process. Our study generated the first big mammalian parthenogenetic animal and demonstrated the feasibility of genome-wide functional engineering, which might be beneficial for biomedical research and agriculture applications.