Scientists have reignited hope about the future of the world's most endangered mammal - the northern white rhino.
Forty-three-year-old Sudan, the then last surviving male northern white rhino on the planet, looks on at Ol Pejeta Conservancy near Nanyuki, some 200 kilometers north of Nairobi, Kenya, on May 3, 2017. To create a self-sustaining population of northern white rhinos with the necessary genetic diversity, scientists will combine stem cell research with other assisted reproduction techniques.
Over the past two decades, attempts at establishing a sustainable northern white rhino population - including natural breeding programs as well as artificial insemination - have been unsuccessful, according to Jan Stejskal, director of communication and worldwide projects at the Dvur Králové Zoo in the Czech Republic, who was involved in the study. "In a second step these germ cells will then be transformed into eggs and sperm", explain Dr Sebastian Diecke, stem cell expert at the Max Delbrueck Center for Molecular Medicine in the Helmholtz Association (MDC) in Berlin, Germany, and Prof Katsuhiko Hayashi, stem cell expert at the Department of Stem Cell Biology and Medicine, Kyushu University, Japan.
There is time pressure, they pointed out, with only two animals still around to socialise the babies in the mysterious ways of northern white rhinos. As scientists hope samples of tissues of such animals will help a modern or future environmentalists to revive these species and restore their populations. The two northern white females can not bear the offspring, and hence, the surrogacy. "They have a very high chance to establish a pregnancy once implanted into a surrogate mother", Hildebrandt said in a statement.
Scientists plan to take egg cells from the still living northern rhinoceros females in autumn of this year, and to fertilize them with stored sperm from the same species.
Decades of rampant poaching have left the northern white rhino on the brink of extinction - with rhino horn fetching up to £40,000 a kilo on the black market. They've already reached out to Ol Pejeta Conservancy in Kenya where those rhinos live and are awaiting permission to attempt the procedure.
These achievements raise the possibility that a hybrid rhino, which preserves numerous genes of the northern white rhino, could be bred in future.
Terri Roth and William Swanson of the Cincinnati Zoo and Botanical Garden, in a comment on the study, said ART alone can not save a species from extinction. Artificial insemination - an assisted reproductive technology - has been used to produce offspring with 60 mammals, including the giant panda, black-footed ferret and Asian elephant, and 35 non-domestic birds.
There are very few frozen eggs of Northern white rhinos, so scientists began oplodotvorenie eggs southern white rhinos saved the sperm of their Northern relatives to create hybrid embryos and to make sure that the technology works.
The researchers had to contend with poor-quality sperm.
"It remains unlikely that a viable population of Northern white rhinos will be restored".
"They have formally said they will give us the necessary support", he said.
"I think it is feasible, but they'll have to hurry", she said. San Diego Zoo is now evaluating six surrogacy candidates, and has already successfully artificially inseminated one with southern white rhino sperm.