Fatu and Najin are the last two Northern White Rhinos on Earth. Being a mother and daughter pair unable to conceive, scientists are turning to genetic and reproductive innovation for hope. Researchers suggest that by utilizing frozen skin cells from deceased rhinos, the Northern White Rhino species may have a chance at recovering from the brink of extinction.
The northern white rhinos Najin and Fatu reside in the Ol Pejeta Conservancy in Kenya. Image Source: Ol Pejeta/DPA/TNS/Alamy Live News
Researchers from the San Diego Zoo Wildlife Alliance in the United States studied skin cells from 12 different northern white rhinos stored in their frozen zoo. This frozen zoo holds genetic material from over 1,000 species. Using computer models, they simulated how if this genetic material from the rhinos were used to produce sperm and egg cells, which could develop into embryos carried by surrogate southern white rhino females, the subspecies would evolve.
The researchers found that it might be possible to restore the population of northern white rhinos after several generations, without the need for Fatu and Najin. Aryn Wilder from the San Diego Zoo Wildlife Alliance stated, "The benefit of having this consistent genomic resource in a frozen zoo is that we can continually pull out new individuals and reintroduce them to the population."
Their models showed that after 10 generations, the simulated northern white rhinos were not inbred; instead, they were a healthy, genetically diverse group. This is good news for the future of the subspecies, as inbred animals are often more susceptible to diseases and less likely to survive.
Wilder then compared the genes of these simulated rhinos to those of southern white rhinos. The southern white rhino population has rebounded from about 100 individuals in the early 20th century to around 20,000 today. She said, "Compared to southern white rhinos, the genome of northern white rhinos actually has more genetic diversity."
Currently, researchers still need to chemically induce these frozen skin cell lines into viable sperm and egg stem cells, with no guarantee that surrogate southern white rhinos can successfully carry northern white rhino embryos. Another approach is cloning—where the stored cell lines could be used to produce genetic copies of deceased animals.
Terri Roth from the Cincinnati Zoo & Botanical Garden said, "Protecting rhinos is far more important than genetic diversity of cell lines. In this challenging time, any good news is worth celebrating."
The related research paper is set to be published in Evolutionary Applications.
