Using stem cells to save rhinos from extinction
The northern white rhino is right on the brink of extinction, with only three of the species left on the planet. There's zero hope for the animals surviving naturally, but a team of scientists believes it might still be possible to bring the species back from the brink, with hopes of using stored genetic information to produce a new population.
The goal of the project is to bring new technologies and approaches to bear in the fight against the animals' otherwise certain extinction. Central to the effort is a need to maintain a genetic bank of frozen tissue, spermatozoa and oocytes of the animals. Those resources have currently been saved in both Europe and San Diego.
Using those materials, the team, which includes scientists from the Leibniz Institute for Zoo and Wildlife Research (IZW) in Berlin and the San Diego Zoo, believes that advanced reproductive technologies, using pluripotent stem cells, could lead to the creation of sperm and egg cells, with in vitro fertilization then used to create embryos that could be used to revitalize the population.
Meeting in Vienna, Austria in December 2015, the international team agreed on a strategic roadmap for making that goal a reality. The idea is to produce a healthy embryo, which will then be implanted it into a southern white rhino, of which some 20,000 still exist.
That process will be problematic, having never been successfully completed before. The team is working with the southern white rhinos to develop the IVF technique, and is confident that it will be overcome the challenge within a matter of years.
Currently, the two surviving female northern white rhinos are the only source of egg cells for use in IVF, meaning that the resulting population wouldn't be diverse enough to survive in the wild. However, a planned second stage of the project would see the researchers attempt to reprogram frozen cells into stem cells that can develop into any sort of tissue, including sperm and egg cells.
While the scientists involved are confident that the project will succeed, it's fair to characterize it as a long shot at this point. But assuming they were successful, it would provide a miraculous turnaround for a species on the edge, and could provide a template for saving other endangered animals.
"Although we were able to breed the northern white rhinoceroses in our zoo, their health status does not allow them to breed naturally any more," said IZW's Professor Thomas Hildebrant. "We are now optimistic that the cutting-edge research outlined in Vienna will give these very last specimens a chance to see an offspring of their own kind."
Full details of the research are published online in the journal Zoo Biology.