There are only two Northern white rhinos left in the world, and scientists are making concerted efforts to save this species from extinction.
According to New Scientist, most of the hope for the future of the Northern white rhino (Ceratotherium simum cottoni) rests on the last surviving members: Fatu and Najin, a mother-daughter pair of rhinos that are infertile. Since neither can conceive, experts are turning to innovations in genetics and reproductive technologies.
The last two Northern white rhinos on Earth are being protected at a sanctuary in Kenya – (Photo: Ol Pejeta/DPA/TNS/Alamy Live News).
Researchers at the San Diego Zoo Wildlife Alliance in California have examined skin cells taken from 12 different Northern white rhinos stored in the Frozen Zoo, a repository of genetic material from over a thousand different species.
They used computer modeling to explore what would happen if the genetic material from these rhinos were used to create sperm and egg cells, which could then be turned into embryos and implanted in a closely related species, the Southern white rhino (Ceratotherium simum simum), for surrogacy.
The team discovered that it may be possible to restore the Northern white rhino population over multiple generations without Fatu and Najin.
“The advantage of having a consistent gene source in the Frozen Zoo is that we can continuously produce new individuals and bring them back into the population,” said researcher Aryn Wilder from the San Diego Zoo Wildlife Alliance.
Their model revealed that after 10 generations, the Northern white rhinos in these simulations would not be inbred. Instead, they would form a healthy, genetically diverse group. This is good news for the subspecies, as inbred animals tend to be more susceptible to diseases and have lower survival rates.
Wilder later compared the genes of the simulated rhinos with those of the Southern white rhino, which has recovered from around 100 individuals in the early 1900s to 20,000 today.
“Compared to the Southern white rhino, the genome of the Northern white rhino actually has higher genetic diversity“, she stated.
Nevertheless, challenges remain. Researchers still need to chemically stimulate these frozen skin cell lines into viable egg and sperm stem cells.
Moreover, there is no guarantee that Southern white rhinos would successfully carry embryos from Northern white rhinos.
Another approach to restoring the Northern white rhino is cloning: the stored cell lines could be used to create genetic copies of deceased animals.
