The northern white rhino is the world's most endangered mammal and its situation became especially desperate when the last male of the species, Sudan, died in March.
Thomas Hildebrandt, head of the Department of Reproduction Management at the Berlin-based Leibniz Institute for Zoo and Wildlife Research (IZW), said that the progress could be a great chance that after embryos are inserted into the womb of the surrogate mother, this female will be pregnant.
Scientists have succeeded in combining frozen sperm from northern white rhinos to fertilise eggs from the closely related souther variety rhino species - the southern white rhino.
IVF has been used before successfully in large mammals, such as horses, but this is the first time that rhino embryos have been developed to the blastocyst stage.
In vitro fertilization is the last hope to save the northern white rhinos, a subspecies of white rhinos, since the last male died in March.
Kock and fellow conservationists warned against focussing only on the northern white rhino sub-species, noting that its southern cousin has come back from the brink of extinction and now numbers some 21,000 individuals.
The paper states how "hybrid" rhino embryos can effectively be formed through IVF, after two decades of unsuccessful conventional methods of Assisted Reproduction Techniques.
'Extreme, dangerous' heat to continue this week, meteorologists say
Heat index values are expected to be up to 107 due to temperatures in the upper 90s and dewpoints in the low 70s. Slightly cooler conditions are expected on Monday as a backdoor cold front approaches from the northeast.
But genes from the northern white rhinos might live on.
Only two of these northern white rhino (NWR) females - a mother and her daughter named Najin and Fatu - are still alive, both are living in Ol Pejeta sanctuary in Kenya.
"Assisted reproductive technologies are very expensive and their success is far from guaranteed".
"ART might offer an option for rescuing genes from the northern white rhino, an essential first step in saving this almost extinct rhinoceros sub-species", the paper published in June states. But it is a tedious and risky procedure which requires a long device to be inserted in the rectum while the rhinos must be put under anesthetic for two hours.
"It is important that we learn from the plight of the northern white rhino and we make sure what happened to it does not happen to other endangered species". Additionally, the global team established stem cell lines from blastocysts of the SWR with typical features of embryonic stem cells. These eggs were then fertilized in petri dishes with previously frozen samples of northern males' sperm. 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.
The scientists' next step is to harvest eggs from Fatu and Najin. Dr. Roth says that poaching is a significant threat to the rhino species. "They have a 16-month pregnancy, so that gives us a little more than a year to have a successful implantation".
"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. They plan to use chemical and genetic techniques to transform these ordinary skin cells into more cells resembling embryonic stem cells. "But we are extremely confident we can get the [eggs] out". According to him, the gradual disappearance occurred due to the fact that grams of the horns of these rhinos were worth more than gold and hunters killed the animals one by one.