The northern white rhinoceros has been in critical danger of extinction for some years, with only a few specimens surviving in the world. In March 2018 Sudan, the last male, died, tarnishing the future of the species, leaving only two females as the only population. However, there was a halo of hope: Sudan’s sperm had been frozen, in the hope that one day sophisticated fertilization techniques could be used to ensure its survival. This species succumbed to poaching; now, it might depend on a lab.
Months after Sudan’s disappearance, scientists were already working on making viable embryos. The mission consisted of collecting oocytes from the two females that still survive and combining them with the sperm of Sudan, who was the father of these. Inbreeding can be a problem for the offspring to thrive. This is where biotechnology comes into play . Thanks to the use of pluripotent stem cells, which can be converted into any tissue in an organism, there are 12 frozen cell lines of northern white rhinos, six of which are genetically distinct. This is key to avoid the aforementioned inbreeding and the viability of the embryo.
Unfortunately today we know that neither of the two females (neither Najin nor Fatuwill) can carry a pregnancy to term, due to their advanced age.
Northern white rhino embryos implanted in females of other subspecies
For this reason, the scientists put in place a plan B: the objective was centered on implantation in female southern white rhinos or hybrid white rhinos from the north to the south, of which there are still 20,000 specimens. Under this plan, hybrid rhinos born from this IVF could be, in the future, more compatible mothers for a potential northern white rhino embryo, as they will share more DNA with the calves. However, this process has a weak point: it is slow. It will take several generations to recover the pure northern white rhino population .
Since the process of collecting oocytes from the females began, this genetic material is being transferred from Kenya to the Avantea Laboratory in Italy, to be artificially inseminated with frozen sperm from Sudan.
So far, three embryos have been created. The next step is to select female southern white rhinos, another subspecies of rhinoceros, in the Ol Pejeta nature reserve, to serve as surrogate mothers. Perfecting in vitro fertilization techniques and keeping the two remaining females alive will be key to saving this species from disappearance.
A snake-shaped ‘inseminator robot’
Faced with the critical situation of the northern white rhinoceros, laboratories around the world began to work to develop technologies that could be put at the service of the survival of the species.
An example of this is the project of the University of California and the San Diego Zoo that in May 2019, which presented an innovative method that could facilitate in vitro fertilization: it is a flexible snake-shaped robot, which would help to zoologists the performance of artificial insemination.
The motivation for this ingenuity, according to the researchers, lies in the peculiar characteristics of the female anatomy: “The rhinoceros cervix is very large and makes a series of turns, like curves on a steep road,” they stated.
If the process continues normal channels, in a short time we will be able to witness the birth of a new specimen of northern white rhinoceros, the first born thanks to IVF. It only remains to wait for the technological miracle to happen.
