Scientists say they performed the first successful embryo transfer on a rhino. They hope to use the technique to save the northern white rhino.Scientists have successfully impregnated a rhino using embryo transfer for the first time, marking a major breakthrough in conservation efforts to save the world's population of the northern white rhinoceros.

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There are currently only two northern white rhinos left on Earth, a mother and a daughter named Najin, 33 years old, and Fatu, age 23.

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Both live in Kenya at Ol Pejeta Conservancy, where they are closely guarded.

The vast majority of the population of the endangered animal were killed by poachers, who reduced the population from around 500 to 15 in the 1970s and 1980s.

At a press conference in Berlin, January 24, researchers for the German government-funded Biorescue project announced they had successfully impregnated a southern white rhinoceros named Curra in September 2023, using egg cells and sperm collected from donor rhinos.

This is significant because it confirms, for the first time, that embryo transfer can work in rhinos. Experts say the ability to do this is crucial for saving the world's white rhino population from extinction.

Researchers have 30 preserved northern white rhino embryos stored in Italy and Germany and awaiting transfer into southern white rhino surrogate mothers.

Pregnancy not carried to term

The sad news, however, is that Curra did not live to deliver a baby rhino.

After a 70-day pregnancy, Curra died in November after extreme flooding set dormant bacteria spores free at Kenya's Ol Pejeta Conservancy, where Curra was under close observation. A toxicology report showed that she died of an infection caused by the spores.

However, the Biorescue researchers say the success of the pregnancy is a good sign that the transfer technique could work in other northern white rhino.

The northern white rhino and southern white rhino have compatible reproductive systems, the researchers said, which makes surrogacy possible.

Cesare Galli, director of Avantea, a lab in Italy, where the embryos were created, said that although Curra's pregnancy had a long way to go, the "chances [had been] very high" — around 70% — that it would have been successful had she lived.

Susanne Holtze, a postdoctoral researcher involved in the project, stressed this breakthrough had involved a "long and bumpy, sometimes windy road."

Curra's pregnancy came after two failed implantations before it, and one ectopic pregnancy, and it had taken five years of work to get from embryo to fetus.

However, Holtze told DW, she was confident that impregnation of a southern white rhino with a northern white rhino embryo will be easier than Curra's impregnation with a southern white rhino embryo, because the outer walls of the southern white rhino oocyte — a basic cell that becomes an egg — are thicker than those of the northern white rhino.

Transfer as soon as June

Researchers say they may manage to transfer a northern white rhino embryo into a southern white rhino surrogate as soon as June 2024.

Northern white rhino pregnancies last 16 months. Once the northern white rhino is born, the researchers said, it will be crucial to integrate it with Fatu and Nijan so it understands itself, and behaves, as the northern white rhino it is.

In order to create a lasting population of northern white rhinos, researchers will not be able to use only the 30 embryos they have stored. All 30 of the eggs are from Fatu. In order to create the genetic diversity needed to sustain a population, researchers said they were planning to use gene editing.

If all goes well, in a few years, the scientists involved in the project may be able to save the rhinos from "disappearing from the face of the Earth," Ol Pejeta Conservancy head of conservation Samuel Mutisya said at the press conference.

Hosting the last-known-to-exist white rhinos is a "huge responsibility," he said.

Edited by: Zulfikar Abbany

(The above story first appeared on LatestLY on Jan 24, 2024 10:30 PM IST. For more news and updates on politics, world, sports, entertainment and lifestyle, log on to our website latestly.com).