Only two northern white rhinos exist in the world: both are female and neither can bear calves. But scientists have not given up hope of saving the species from extinction.
They succeeded last year in creating hybrid embryos using frozen northern white rhino sperm and eggs from a southern white rhino, a closely related sub-species.
Now they are working on how to implant the embryos into a surrogate mother to bring them to term, and once they've mastered that, they can create purebred northern white rhino embryos that would be carried by a southern white.
As part of that work a team led by Thomas Hildebrandt of the Leibniz Institute for Zoo and Wildlife Research in Berlin harvested egg cells from a female southern white rhino, 17-year-old Hope, at a zoo park in the Polish city of Chorzow.
They have recently done the same with selected southern white rhinos about 18 times in zoos across Europe.
With the size of a rhino and its weight of about two tons, it was another challenge for the scientists to find a way of harvesting the eggs without harming the animal.
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Two northern white rhinos exist in the world but they are both unable to have offspring and there are no males of this species left in existence after the death of Sudan in March 2018
Team of experts led by Thomas Hildebrandt, right down, of the Leibniz Institute for Zoo and Wildlife Research in Berlin have Scientists have harvested eggs of a female southern white rhino and hope to fertilise them with the sperm of the extinct northern males
As the ovaries are about two meters inside, they inserted an instrument they created for this purpose containing an ultrasound camera with a needle through the anus and into the ovarian tissue.
'It's a little bit like rocket science because there is no example which we can follow because we are the first in this field we developed everything from scratch,'Dr Hildebrandt said.
Since the remaining northern females, a mother and daughter called Najin and Fatu who live in Kenya, are unable to bear offspring themselves, the embryos created from their eggs will be implanted into a southern white rhino surrogate.
The process of implantation is what the scientists are now trying to perfect. Only when they master it can they risk using the egg cells of the two surviving rhinos and preserved sperm to produce 'pure' northern white rhino, to be carried by a southern white surrogate. They hope to achieve this in less than three years.
'First, we have to optimise the method of implanting the embryos,' said Jan Stejskal, a spokesman for Dvur Kralove Zoo in the Czech Republic, which has a long history of rhino conservation and from which the last two females were taken to Kenya several years ago.
'We expect to be close to perfecting the method in several months,' Mr Stejskal said.
HOW DO SCIENTISTS HOPE TO SAVE THE NORTHERN WHITE RHINO USING IVF?
Scientists are hoping to use IVF and stem cell techniques developed for humans to resurrect the northern white rhino - but the process is fraught with challenges
While the death of Sudan marks a symbolic turning point in the fight to save the northern white rhino, in fact the survival of the species has been entirely reliant on untested IVF techniques for years.
It was hoped that Sudan, his daughter Najin and granddaughter Patu might be able to produce offspring when they were moved to Kenya in 2009, but their close genetic relationship rendered them infertile.
Since at least 2015 scientists have been working with IVF and stem cell techniques in the hopes of being able to create a viable northern white rhino embryo, according to a GoFundMe page for the project.
Researchers in Berlin and San Diego are using DNA samples collected from a dozen northern whites, including Sudan, and trying to apply techniques developed for humans to the animal.
If a viable embryo can be created, it would then have to be implanted into the womb of a southern white rhino, since Majin and Patu will likely be dead before the technique is perfected.
While the southern white rhino would be responsible for giving birth to the baby, because the infant's genetic material came solely from northern whites, it would be a member of that species.
However, as Save The Rhino points out, the process is fraught with difficulty and has a low chance of success.
In the last 15 years just 10 rhino births have resulted from artificial insemination and only two embryos have ever been created - one of which divided into two cells before perishing, and the other one into three.
For the northern white rhino to be genetically viable a minimum of 20 healthy individuals must be born - meaning the whole process must be successfully completed 20 times - to avoid inbreeding.
Then, it would be necessary to find a suitable habitat for them, since their old habitat has largely been destroyed and led the species to the brink of extinction in the first place.
Team of experts harvested egg cells from a female southern white rhino, 17-year-old Hope, at a zoo park in the Polish city of Chorzow
Team of experts led by Thomas Hildebrandt, centre, of the Leibniz Institute for Zoo and Wildlife Research in Berlin, harvests the eggs
Experts recently did the same procedure with selected southern white rhinos about 18 times in zoos across Europe. With the size of a rhino and its weight of about two tons, it was another challenge for the scientists to find a way of harvesting the eggs without harming the animal
This female rhino and the procedure may be the last hope for the last two northern white rhinos left in the world. Scientists are hoping to salvage the species by using the eggs of southern white rhinos
Female southern white rhino, 17-year-old Hope, is shot with tranquillising darts, so a team of experts can harvest her eggs, at a zoo park in Poland
Anesthesiologists Frank Goeritz checks on 17-year-old Hope, as team of experts harvests the eggs from the animal at a zoo park in Chorzow, Poland
Thomas Hildebrandt of the Leibniz Institute for Zoo and Wildlife Research in Berlin examines samples after harvesting eggs from female southern white rhino
Thomas Hildebrandt of the Leibniz Institute for Zoo and Wildlife Research in Berlin examines samples. If they are viable they may be implanted with sperm from a now-dead male northern white rhino to try and salvage the dying species
Anaesthesiologists Frank Goeritz prepares to sedate female southern white rhino, 17-year-old Hope, so a team of experts can harvest the eggs
The anaesthesiologist fires the tranquillising dart at the rhino to sedate it. The procedure was described as 'a little bit like rocket science because there is no example which we can follow'
Link hienalouca.com
https://hienalouca.com/2019/02/15/surrogate-mother-offers-hope-for-endangered-northern-white-rhino/
Main photo article Only two northern white rhinos exist in the world: both are female and neither can bear calves. But scientists have not given up hope of saving the species from extinction.
They succeeded last year in creating hybrid embryos using frozen northern white rhino sperm and eggs from a southern white...
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Dianne Reeves Online news HienaLouca
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