This species is extremely rare, with only two individuals left in the world, and scientists are striving to save it from extinction.
Najin and Fatu, a mother and daughter pair of rhinos who are both infertile, are the last remaining individuals of the Northern White Rhinoceros (Ceratotherium simum cottoni).
This species was once found throughout Central Africa but has been nearly wiped out due to illegal poaching and now stands on the brink of extinction.
Fujin and Najin grazing together, they are the last two individuals of a species that is critically endangered. (Photo: Justin Mott/Washington Post).
However, since both Najin and Fatu cannot become pregnant, experts are turning to innovative genetic and reproductive strategies.
Researchers at the San Diego Zoo Wildlife Alliance in California have examined skin cells taken from 12 different Northern White Rhinoceros specimens stored in the Frozen Zoo, a repository of genetic material from over a thousand different species.
They used computer models to predict how the genetic material from these rhinos could be used to create viable sperm and egg cells, which could then develop into embryos carried by a closely related species, the Southern White Rhinoceros (Ceratotherium simum simum).
The last two Northern White Rhinos on Earth.
The team discovered that it is possible to restore the Northern White Rhinoceros population over several generations without the need for Fatu and Najin.
“Having a consistent gene source in the Frozen Zoo allows us to continuously create new individuals and reintroduce them to the population,” said researcher Aryn Wilder at 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 future of the subspecies, as inbred animals tend to be more susceptible to diseases and less likely to survive.
However, the path to complete success remains long and challenging. Researchers must chemically stimulate these frozen skin cell lines into viable egg and sperm stem cells.
There is also no guarantee that Southern White Rhinos can successfully carry the embryos of Northern White Rhinos.
Even if embryo transfer is successful, the pregnancy process would need to be closely monitored and nurtured, and even if a healthy rhino is born, substantial breeding efforts will be required to establish a viable population.
Nevertheless, another method to restore the Northern White Rhinoceros is through cloning: the stored cell lines could be used to create genetic copies of deceased animals.
The White Rhinoceros (Ceratotherium simum) is distributed in southern Africa. This species measures 3.4 to 3.8 meters in length, characterized by a wide “square lip” for grazing on the ground, two large horns, and a hump at the back of the neck. It is the largest living rhino species. There are two subspecies of the White Rhinoceros: the Southern White Rhinoceros and the Northern White Rhinoceros. The Southern White Rhinoceros is the most populous rhino species in the world, with a population of about 20,000 individuals. They are listed as near threatened on the IUCN Red List. In contrast to the Southern subspecies, only two Northern White Rhinos remain. The final hope for the survival of this subspecies lies in the genetic technology of the future. |
