A team of international scientists at the Leibniz Institute for Zoo and Wildlife Research has successfully transferred the first test tube rhino embryo into a surrogate southern white rhinoceros. Now, they hope to use the same procedure with the sperm and eggs of northern white rhinos, a species whose population has dwindled to two females no longer capable of carrying offspring themselves.
Researchers transferred the embryo into the uterus of a southern white rhino – the species most closely related to its northern counterpart – at the end of May 2019. Earlier this week, they announced the transfer was successful in what they deem an important milestone in using reproduction and stem cell technology to ensure the survival of species on the extinction cutting block.
Just before the death of the world’s last northern white rhino in March 2018, scientists collected his semen and have stored it in liquid nitrogen ever since. Today, only two females remain, Najin and Fatu, where they live in the Ol Pejeta Conservancy in Kenya but are no longer able to carry offspring themselves. Researchers now hope to harvest their eggs and expose it to the sperm in an in vitro fertilization (IVF) procedure before transferring the fertilized embryos into the uterus of a southern white rhino, who will act as a surrogate mother.
It’s new territory and has never been performed before. Given the limited global supply of northern white rhino sperm, the team wanted to make sure they were successfully able to perform such a procedure.
But the biological clock is ticking. Researchers say they are waiting to receive the proper paperwork to harvest the northern white rhino egg, reports the Associated Press. They are quick to caution that the embryo is still smaller than expected and it's yet to be determined whether it will successfully implant in the uterine lining and result in a pregnancy.
Established by Germany’s Federal Ministry of Education and Research, the BioRescue project says their work will play an important role in developing methods and techniques for the conservation of diversity to save endangered species.
“Within this initiative, we primarily focus on promoting precautionary research aimed at preserving biodiversity. Parallel to this, we also facilitate immediate measures to protect endangered species, such as the ambitious BioRescue project,” said Michael Meister, Parliamentary State Secretary, in a statement. “Thanks to the impressive combination of different research approaches and the great dedication shown by those involved, there is now both the possibility and the hope that we will be able to preserve critically endangered species such as the northern white rhinoceros.”
Generally speaking, the International Union For Conservation of Nature reports that rhino populations are increasing throughout Africa for the first time in decades, but the northern white rhino (Ceratotherium simum cottoni) has been nearly forced to extinction largely due to human activity.