There are three northern white rhinos left in the world – two females, one male. When they are gone the subspecies will be extinct. The existing rhinos are not capable of reproducing for multiple medical reasons. This article in Nature describes the cutting edge reproductive science that two research teams hope to apply to save the subspecies.
…researchers this week unveiled the details of an audacious plan to save the northern white rhino (Ceratotherium simum cottoni), by transforming cells from living rhinos and from frozen storage into sperm and egg cells, and then using in vitro fertilization (IVF) to create embryos and revitalize the population. Teams led by San Diego Zoo Global in California and the Leibniz Institute for Zoo and Wildlife Research in Berlin have already started work on the idea.
The first phase of this project centers around in vitro fertilization of eggs harvested from the two remaining females with sperm from samples collected and frozen in the past. As neither female is considered physical capable of dealing with the rigors of a pregnancy, the researchers intend to use a female southern white rhino as a surrogate. Success is this phase requires developing a viable in vitro process.
But no one has ever made a viable rhino embryo using IVF, let alone implanted one into a surrogate, so the San Diego and Leibniz teams are each working to develop the technique in southern white rhinos, which number around 20,000.
Assuming that the in vitro process works and produces healthy northern white rhino calves that might be the easy part of the project. The gene pool, based on just the two females and a very limited number of males, will lack the diversity necessary to assure its viability. Phase two involves the modification of frozen rhino cells into stem cells (induced pluripotent stem – iPS) capable of growing as sperm and egg cells.
But generating sperm and eggs from iPS cells will not be simple, and could require rhino stem cells to be cultured alongside the reproductive tissue of other animals, such as mice.
This is where saving endangered species begins to move into controversial territory. Utilizing new techniques and medical technology to literally save a species from extinction has tremendous appeal. Taking that a step further, why not bring back extinct species (assuming that the appropriate viable cell samples were available). The line between can do and should do gets hazy at this point.
First is the question of cost. Is it right to spend millions of dollars to save the northern white rhino, when that money could be spent on more practical conservation projects for species with much better chances of long term survival .
Second, is the Jurassic Park dilemma. Just because we can do something this complex and expensive doesn’t mean that we should do it. Could demonstrating that we can save this species through these actions result in a change in the mind set of endangered species conservation?
That precedent is what most worries Stuart Pimm, a conservation biologist at Duke University in Durham, North Carolina. “This says we can let species go to the very brink of extinction and modern technology can bring them back,” he says. “There is a very substantial moral hazard in that.”
The moral dilemma cuts both ways and even challenges our premise at Just Save One.