Scientists step toward saving rhinoceros

Tsuyoshi Matsumoto / Yomiuri Shimbun file photo
Northern white rhinos are seen in Ol Pejeta Conservancy, Kenya, in September, 2018.

TOKYO (Jiji Press) — An international team including Osaka University has succeeded in creating cells possibly developing into reproductive cells of the northern white rhinoceros, which might pave the way for saving the species on the verge of extinction.

The team has created primordial germ cell-like cells of the rhino in vitro, in the world’s first production of PGC-like cells from induced pluripotent stem, or iPS, cells derived from a wild animal. PGC-like cells are the source of sperm and eggs.

The team, including Masafumi Hayashi, a researcher at an Osaka University graduate school, and German and Italian scientists, published an article on the research in U.S. journal Science Advances on Dec. 9.

The northern white rhino used to inhabit the central African continent, but illegal hunting and destruction of nature have drastically reduced its population. The species became extinct in the wild in 2008.

Two males and two females were then relocated to Kenya from a zoo. But the males have since died, making natural mating impossible because the two females are the only remaining northern white rhinos in the world.

The team first developed a technology to produce PGC-like cells from embryonic stem, or ES, cells of the closely related southern white rhinoceros. Applying this technology, the team created PGC-like cells from iPS cells made from skin cells of the northern white rhino.

An artificial insemination technology has already been developed for the northern white rhino, and male sperm has been cryopreserved.

Once a technology to mature the PGC-like cells into eggs is established, it will become possible to breed the species using the preserved sperm, according to the team. Currently, it is expected to take four to five years to produce northern white rhino eggs from the PGC cells.