Researchers create endangered white rhino hybrid embryos

The northern white rhinoceros, almost extinct, may not be completely lost.

For the first time, rhinoceros embryos were made in the laboratory. Scientists injected sperm from a northern white rhino into female white rhino eggs, a closely related subspecies. The embryos were incubated until the cells began to differentiate, a step at which they can be implanted in a surrogate mother, the researchers report July 4 in Nature Communications .

The new feat is "one of the truly" According to the co-author of the study, Jan Stejskal, coordinator of conservation efforts of white rhinos in Safari Park Dvůr Králové in the Czech Republic, " crucial steps to produce new rhinoceros calves ". Finally, the researchers hope to implant similar embryos in southern female white rhinos or hybrid white rhinos in the north and south.

If it works, it could give the hope of bringing a species back to the brink of extinction. Sudan, the last male northern white rhino, died in March. Only two females remain in Kenya in captivity and unable to reproduce naturally. In comparison, there are still more than 20,000 southern white rhinos

. In the new study, scientists used southern female white rhinoceros eggs and sperm preserved in three northern white male rhinoceros. While the new embryos are a mixture of north-south hybrid white rhinos, their ability to create them is "a saving mechanism for the northern white rhinoceros genes," says Thomas Hildebrandt, co-author of the 39; study to & # 39; Leibniz Institute research wildlife Berlin

Hybrid rhinos, if they were born, could serve two purposes: they could be mothers More Compatible Carriers In theory, hybrids could be selected for northern rhinoceros genes, creating a pure Northern White Rhino – a process that would take many generations and extend over several generations – several decades

In a potentially faster way to give birth to a pure northern white rhinoceros, researchers plan to harvest eggs from the remaining two females and combine them with preserved northern white rhinoceros sperm over the next three years. , says Hildebrandt.

Stem cell technology can also play an important role in rhinoceros saving: the team has been able to derive from s pluripotent stem cells that can be transformed into any cell in the body. including ova and sperm, from two pure white embryos from the south. Hildebrandt says that there are 12 frozen lines of northern white rhinos, six of which are genetically distinct – important to avoid inbreeding. If researchers can turn these skin cells into pluripotent stem cells and then into eggs and sperm cells, that would be another way to create a pure white rhinoceros embryo from the North.

For now, other scientists warn against too much optimism. "Saving a species or subspecies takes a lot more than science," says Terri Roth, an animal reproduction physiologist at the Cincinnati Zoo and Botanical Garden. Africa is in the midst of an epidemic of rhino-poaching, she says. In 2013, poachers killed 13 rhinos; in 2017, more than 1,000 were killed. Efforts to restore the northern white rhinoceros population will need to address this crisis, she says ( SN Online: 16.12.13 ).

Hildebrandt agrees. The northern white rhino has not turned off because he's failed to evolve, he says, "he failed because he's not at the Bulletproof. "