Bipaternal Mice Born from Two Male Parents Mark Milestone in Genetic Engineering

A team of Chinese scientists has achieved a pioneering breakthrough by creating bipaternal mice—offspring derived from two male parents—using advanced gene-editing techniques on embryonic stem cells. Unlike natural sexual reproduction in mammals, this process involved modifying a set of about 20 imprinted genes to bypass the typical need for a female genetic contribution. To accomplish this feat, researchers combined genome editing with cloning technologies, producing over a thousand embryos. Although only a modest percentage of these embryos survived, and many of the resulting pups exhibited severe defects such as craniofacial deformities and suckling difficulties, the experiment represents a significant step forward in the field of mammalian genetic engineering.

The study, which was documented in a leading scientific journal, highlights not only the technical challenges but also the potential practical applications of the research. The scientists noted that, if further refined, the technique might be useful in conservation efforts for critically endangered species by enabling reproduction without relying on both sexes. Additionally, the findings offer promising insights into the broader realm of regenerative medicine, where understanding and harnessing the pluripotency of stem cells is a key objective.

Despite the groundbreaking nature of the experiment, the bipaternal mice that reached adulthood were not without problems. They suffered from developmental disorders, had shortened lifespans, and were unable to reproduce, suggesting that the extensive modifications to key imprinted genes had unforeseen biological repercussions. Researchers observed not only physical defects but also behavioral abnormalities, pointing to the complex role these genes play in normal development.

The work builds on previous studies in the field and offers a contrast to alternative methods that achieve similar outcomes without extensive genome editing. While another team, for example, generated bipaternal mice using induced pluripotent stem cells with fewer adverse effects, the Chinese research emphasizes the impact of controlled genetic modifications on embryonic stem cell pluripotency. Ultimately, the insight into genomic imprinting gained from this work is poised to enrich the scientific understanding of mammalian development and potentially reshape future strategies in both medicine and conservation.