A group of scientists associated with the San Diego Frozen Zoo expresses their plan of resurrecting the nearly extinct Northern White Rhino population through genetic engineering of the species' DNA.
Only two females were left of the species when the last male, Sudan, died in March. There are no other species left of them even in the wild, as the two female rhinos were being kept in captivity for their protection.
Oliver Ryder, director of conservation genetics at San Diego Zoo Global, said that given a suitable assisted reproduction or advanced cloning technology, the whole population of the Northern White Rhino could be resurrected.
Frozen Northern White Rhino Cells
Ryder and his colleagues will try to recover the Northern White Rhino population using the animals' cryopreserved cells that are being stored at the Frozen Zoo facility.
First, the team investigated the genetic history of nine cryopreserved cell lines of the Northern White Rhino through DNA sequencing. This produced the very first genome sequencing of the species despite still being incomplete, the researchers said. Nevertheless, their work could already serve as the foundation of the planned recovery program for the nearly extinct Northern White Rhino.
Second, the team compared their DNA analysis of the Northern White Rhino to the cells of the Southern White Rhino, the animals' closest related subspecies. The analysis, published in Genome Research, revealed that the two groups of rhinos had separated some 80,000 years ago and had evolved with genetic variations.
Nevertheless, even with the genetic differences between the two species, the lineage seen in them remained the closest when compared to the lineage of other extinct species that other scientists are planning to clone. This discovery became particularly promising, as the San Diego Zoo had successfully impregnated a Southern White Rhino through artificial insemination. The team was positive that mothers from the subspecies could carry the babies of the Northern White Rhino in the future.
"The [Southern White Rhino] went through a severe genetic bottleneck, but is now the most populous of all forms of rhino at 20,000 individuals, suggesting that a genetic rescue utilizing these cell lines could be the foundation for a similar recovery in the [Northern White Rhino]," said Tate Tunstall, lead author of the study and a scientist from the San Diego Zoo Institute for Conservation Research.
Resurrection Of Northern White Rhino Population
The team's plan, although still at an early stage, was already met with criticisms.
Marty Kardos, an evolutionary biology researcher at the University of Montana, expressed concerns about possible harmful mutations when the Northern White Rhino and Southern White Rhino were combined.
Jason Gilchrist, an ecologist at Edinburgh Napier University in Scotland, was cautious about reviving a species that could no longer live in their natural habitat. In the case of the Northern White Rhino, illegal poaching activities in Africa were a big factor in their extinction. Gilchrist could not see the point of resurrecting their population if the entire species would merely stay in captivity.
