"An global team of scientists has now successfully created hybrid embryos from Southern White Rhino (SWR) eggs and Northern White Rhino sperm using assisted reproduction techniques (ART)", the researchers from Avantea, a laboratory of advanced technologies for biotechnology research and animal reproduction, noted in a statement.
"They showed that oocytes can be repeatedly recovered from live females by this trans-rectal ovum pick-up, matured, fertilised by intracytoplasmic sperm injection (ICSI) and, for the first time, developed to the blastocyst stage in vitro".
A major embryo breakthrough could help save one of the most endangered animals on the planet, and many more in the future.
In March, the last male northern white rhinoceros (NWR) died, leaving behind just two females of the subspecies.
The result is the very first generation of pre-implantation embryos of rhinos in a test tube. The two northern white females can not bear the offspring, and hence, the surrogacy.
"Our results indicate that ART (assisted reproduction techniques) could be a viable strategy to rescue genes from the iconic, nearly extinct, northern white rhinoceros", the team wrote in the journal Nature Communications.
"Rhinos are very large (2,000 kg on average), so they have a reproductive tract that is very hard to access".
Professor Thomas Hildebrandt, head of reproduction management at the Leibniz Institute for Zoo and Wildlife Research in Berlin, Germany said, "These are the first in-vitro produced rhinoceros embryos ever".
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As for the female eggs, they were taken from the southern white rhinoceros from several European zoo parks, including the Dvur Kralove Zoo.
It is possible that in the future, a female that's a hybrid of the northern and southern rhinos could carry a fully northern white rhino baby to term. The embryos reached the blastocyst stage-a relatively developed stage which boosts the chances of pregnancy after transplantation. This final step toward the birth of a calf containing northern white rhino DNA is no small step, as artificial insemination in rhino has rarely been attempted. Some of this sperm was injected into egg cells taken from females of the southern white rhino subspecies.
"This is quite the technological feat", said David E. Wildt, senior scientist at the Smithsonian Conservation Biology Institute, who was not involved with this research.
Researchers have discovered new leads in stem cell research, by breeding white rhinos artificially using lab-grown embryos, in a bid to stop a complete wipe out of the endangered white rhino species.
The Chicago Tribune's Frank Jordans writes that scientists' long-term goal is to harvest eggs from Najin and Fatu, thereby enabling them to create wholly northern rhino embryos. These cells are adult cells, such as blood or skin cells, that are reprogrammed to act like stem cells.
Following Sudan's death, scientists began to look for new ways to restore the species, on the verge of extinction because of the lack of male specimens due to poaching.
Many scientists see these technologies as a valuable tool in the repopulation of disappearing species. This method has previously been used successfully with mice.
"The concern in the conservation community is that people will hear this and think, 'We can save the rhinos with science and then become more complacent about the other strategies we have in action now, '" Roth said as cited by CNN. "We ... were highly afraid that something unexpected would happen during this procedure", Hildebrandt told a telephone briefing.
Roth doesn't believe that one size will fit all. We can not afford to adopt a cavalier attitude toward extinction, as though animals were something to bring back at our leisure, he said.