Scientists hope IVF will bring rhino back to life
Tiny sacs of cells may look like meaningless blobs but they hold the embryo of a northern white rhino – and the future of a sub-species.
The northern white rhino has been effectively extinct since
2018, when the last male, 45-yearold Sudan, died in Kenya.
Since the 1960s, the population has fallen from 2000 to just two remaining females today – mother Najin and daughter Fatu – who are currently protected at the Ol Pejeta Conservancy near Mt Kenya.
But now scientists have taken nine eggs from the females and fertilised them with sperm from a dead male, successfully creating three viable embryos that they are hoping to implant into a surrogate later this year.
All three embryos are now stored in liquid nitrogen while conservationists hunt for a suitable female to carry the precious calves.
The team is hoping to implant the embryos into young, fertile southern white rhinos, as it is too risky to carry out the procedure on the last remaining northerns.
The gestation period for rhinos is up to 18 months, meaning the first northern white rhino calf could be born by 2022.
‘‘This is a big win for Kenya and the northern white rhino,’’ said Najib Balala, Kenya’s secretary for tourism.
‘‘We thank the concerned parties for putting in all their efforts to ensure that a critically endangered species does not disappear from the planet under our watch. It is amazing to see that we will be able to reverse the tragic loss of this sub-species through science.’’
Northern white rhinos are the most endangered mammal on Earth; until now, efforts to save them have been thwarted by civil war, poaching and habitat loss.
The task of taking egg cells from a rhino had never been attempted before, and scientists had to invent a special 1.8-metre device to stimulate the female’s ovaries and collect the oocytes.
Researchers say the creation of three pure northern embryos is a ‘‘hugely encouraging milestone’’ for the species and it was accomplished using a safe procedure that can be performed on a regular basis until the animals get too old.
Following fertilisation, the embryos were monitored in a special incubator, dubbed Geri, which was supplied by German pharmaceutical company Merck. The scientists are also trying to create rhino sperm and eggs directly from stem cells.
Because there are only two females left and all the available semen comes from only four males, in-vitro fertilisation alone would not be able to create a selfsustaining population of northern white rhinos with the necessary genetic diversity.
To get around that, scientists are working on producing artificial gametes – egg and sperm – from the preserved ear tissue of 12 dead white rhinos.
The scientists say the work creates a blueprint for how to save endangered species – even those that are already extinct.
Once they have a viable population, the rhinos will be taken back to central Africa.
Meanwhile, a black rhino calf was born on Christmas Eve at a zoo in Michigan. The species is critically endangered, the result of poaching and loss of habitat.
About 5000 black rhinos exist in the African wild, which is up from their low numbers 20 years ago when the population was less than 2500 and on the brink of extinction, according to the World Wildlife Fund. Less than two black rhino calves are born in human care each year.