Bringing back the northern white rhino from ‘extinction’

Just one of two remaininn—but hopefully not for long

Just one of two remaininn—but hopefully not for long

When the world's last northern white rhinoceros male died in March (above), researchers scrambled to save the species-which had only two females left.

"We thought, 'The story's over, '" said Dr Hildebrandt, a wildlife reproductive biologist at the Leibniz Institute for Zoo and Wildlife Research and the Free University of Berlin.

They are also working on a second method that would see sperm and eggs produced from preserved cells of northern white rhinos. The successful implantation was a first involving an embryo from a test tube implanted into a rhino.

However, latest scientific advances in stem cell research brought Dr Hildebrandt and his worldwide team new hope in resurrecting the species.

"In the near future we are planning to go to Kenya to retrieve the eggs from the bodies of two female Northern white rhinos".

The worldwide team believes that assisted reproduction technologies used for other large mammals, including horses and cows, could be transferred to the surviving northern white rhinos as a way of boosting their reproductive capacity.

But genes from the northern white rhinos might live on. "Our results are solid, reproducible and very promising".

Several generations of intensive interbreeding would dilute out the southern white rhino genes, "getting us to the point where we basically have a 99 percent northern white rhino", says Terri Roth, vice-president of conservation and science and CREW director at the Cincinnati Zoo and Botanical Garden, who was not involved in the study. That process requires full anesthesia and poses a risk to the rhino. "We've made a test-tube rhino".

To broaden the genetic diversity beyond the few individuals left, they plan to artificially generate oocytes from banked somatic cells of northern white rhinos that could be coaxed into gametes using stem cell technology, according to the paper. So far, they have generated 12 rhino stem cell lines, Hildebrandt said.

The female eggs ended in the laboratory of Avantea in Italy, the world's leader in artificial reproduction for large animals.

To produce healthy rhinoceros calves, the fertilized egg cells must be implanted into healthy rhinoceros females of reproductive age.

The authors performed 18 of these procedures on southern white rhinos in zoos across Europe, resulting in the collection of 83 eggs. To retrieve eggs, the researchers put the animal under anesthesia, and then used an ultrasound machine to guide a long needle into her uterus, puncture her follicles and dislodge the eggs.

The scientists' next step is to transfer the frozen embryos to a surrogate southern white rhino mother and carry a pregnancy to term.

For the researchers, however, a combination of ART and stem cell techniques, could "provide a blueprint on how to save highly endangered species that have already dwindled to numbers that make conventional conservation efforts impossible".

"I have no doubt that its purely scientific merit is laudable and it might have some application to endangered species conservation in the future", said Richard Kock, a conservationist at Britain's Royal Veterinary College who has worked extensively in Africa.

Loss of habitat is the other primary threat to rhinos, and conservationists say that governmental protection of parks and reserves is now essential. "But we are extremely confident we can get the [eggs] out". They failed because rhino horns, gram for gram, are more valuable than gold - fetching high prices as status symbols or for their medicinal powders.

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