White Rhinos’ Cells Have Been Converted Into Sperm & Egg Cells To Save Species
Photo 1025015 © Ecophoto | Dreamstime.com
There are only two northern white rhinos (Ceratotherium simum cottoni) in existence, and they’re both female. When they die, their entire species will vanish.
The last male of the subspecies, named Sudan, passed away in March 2018. With no one to help continue the lineage, northern white rhinos are set for extinction. Scientists are hoping to save them from their doom with lab-grown embryos—the product of sperm from deceased male rhinos, including Sudan, and egg cells collected from Najin and her daughter Fatu, the only living northern white rhinoceroses.
Previous experiments have yielded 22 northern white rhino embryos, which have been frozen to be implanted in southern white rhinos (C. simum simum) sometime in the future. Najin, 32, is of age and can no longer carry a baby, leaving her daughter to rescue the whole population. To alleviate Fatu of some of the pressure, researchers are turning to their closely-related subspecies, of which about 20,000 still remain, as surrogates.
In their latest breakthrough, the team has converted skin cells from southern white rhinoceroses into stem cells, creating blank-canvas cells that can be “edited” to promote desired functions—in this case, turn them into sperm and egg cells.
The researchers, led by Katsuhiko Hayashi at Osaka University in Japan, first added skin cells from a deceased female northern white rhino to a cocktail of chemicals and converted them into stem cells. This sample allowed them to study the growth factors and chemical changes required to turn the stem cells of the less-threatened southern white rhinos into sperm and egg cells, called primordial germ cell-like cells.
Once they found the right balance, the scientists experimented on the southern white rhino cells, before practicing on the rarer northern white rhino stem cells and learning they were applicable both ways. They’ve documented their findings in the Science Advances journal.
Don’t expect to see a baby boom of northern white rhinos in the foreseeable future, though. It’s still unclear how fertilized, lab-grown embryos will react to the egg and sperm stem cells. It’s also too early to know if the southern white rhinos will be suitable surrogates for the northern white rhino embryos. No one said this is an easy tusk.
[via New Scientist and Freethink, cover photo 1025015 © Ecophoto | Dreamstime.com]
