Embryo Breakthrough Could Save Nearly Extinct White Rhinos

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The survival prospects of the nearly extinct northern white rhinoceros seemed bleak for years. But their fate could turn around with an in-vitro fertilization method to develop “test-tube rhinos.”

A paper published in the journal Nature Communications avers that scientists have used stored sperm from the last white rhino male – Sudan who died in March – to fertilize eggs from southern white rhinos, close relatives to the northern species.

Two of the resulting hybrid embryos, who started their lives in lab dishes, have been frozen for later implementation, although such a transfer procedure is yet to be developed for rhinos.

While scientists have developed assisted-reproduction technologies for some 60 other large mammals such as cows and horses, this is the first time lab-grown rhino embryos have reached the point where they could be implanted into a uterus.

Researchers hope they could build on their recent breakthrough and create pure white rhino embryos. To be able to do so, the team will need to extract eggs from the two remaining female white rhinos, Fatu and Najin, who live in a protected sanctuary in Kenya.

According to NPR, the team awaits permission to obtain Fatu and Najin’s eggs. Jan Stejskal, of the Dvur Kralove Zoo in the Czech Republic, told the outlet he hopes his colleagues can collect the precious cells by the end of the year.

“Our goal is that we have, in three years, the first northern white rhino calf born,” said Thomas Hildebrandt, of the Leibniz Institute for Zoo and Wildlife Research in Berlin.

Because of the many biological and technological uncertainties that dot the leap from an embryo to a healthy rhino baby, scientists are looking into a years-long process and mulling different possibilities.

For one, the creation of hybrid northern and southern white rhinos could lead to nearly pure northern specimen after generations of inbreeding that would dilute southern genes.

Embryonic stem cell lines, which have been produced with the southern white rhino, provide another option. Hildebrandt said that the induction of sperm and eggs from northern white rhino’s blood or skin cells could take a decade. A southern white rhino could then carry the resultant embryos to full term.

Terri Roth, director of the Center for Conservation and Research of Endangered Wildlife at the Cincinnati Zoo & Botanical Garden, however, sees tech-laded reproduction as “highly speculative” and an indication that all other conservation efforts have failed.

“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.