A friesland clone was born to a cross simmentaler recipient cow on April 19, 2003 as a result of an inter-continental collaboration between the Danish Institute of Agricultural Sciences at Foulum and Embryo Plus, a South African Embryo Technology centre.
The heifer calf in Brits is derived from cells of a stud cow belonging to Mr Schoeman of Grootpan Farm in the Bothaville district. The birth of this heifer represents an important scientific step towards developing techniques that may one day increase the genetic diversity within selected populations of endangered wildlife species.
The initial step to this process occurred in July 2002, with the transfer of genetic material from the donor cow to an “empty” egg of another cow, before being transferred into the uterus of a recipient cow. The calf was delivered by cesarean section.
The live birth of this calf signifies Africa entering the hi-tech animal breeding arena, technology that is destined to play a role in both animal biotechnology and potentially, endangered species conservation.
Cloning, ironically, has the potential to contribute to genetic diversity within a critically endangered animal species. It certainly is not the first choice for breeding an endangered species, but with a handful of species, we may not have a choice in the matter.
The aim of any manager tasked with saving a critically endangered species is to use as big a founder population (e.g. as maximum number of individuals remaining) as possible to quickly grow the population, with all the means at his disposal.
Natural breeding may occur in less than half (effective population) the total remaining population, with the balance not contributing to the survival of the species. With a critically endangered species, it is important to also include the non-breeders gene pool within the founder population, so as to provide the resultant population with the broadest possible gene diversity.
Theoretically, cloning can assist in the conservation of gene diversity in two ways. If a species numbers are down to critical levels (there are a number around the world today, see IUCN Red Data book), then genetic diversity may be broadened if cells from previously banked tissue (when the number of animals was high) are “infused” through cloning back into the relic animal population.
This is where the greatest contribution from cloning could be made to the gene diversity within that population. For an example: Two banteng clones were born to Angus cows on April 1 and 3, 2003 as a result of a cross-continental collaboration involving the Zoological Society of San Diego, a Massachusetts laboratory and an Iowa embryo technology firm.
The banteng is a wild bovine species from the forests of Southeast Asia and is closely related to the domesticated cow. The calves in Iowa are derived from cells of a male banteng who died at the San Diego Wild Animal Park in 1980 without producing offspring. The birth of these two youngsters represents an important scientific step towards developing techniques that increase the genetic population of endangered species.
Secondly, within any critically endangered population (any population for that matter), there are always individuals that do not contribute to reproduction, resulting in a further worsening of the genetic “bottle-neck” situation. Cloning could force the inclusion of genes from the non-contributing individuals back into the remaining population and so give a particular population it’s best shot at survival into the future.
Priority one will always be the conservation of an endangered species within its natural habitat. Unfortunately, this is not always possible. An example is the black rhino, where although there remains abundant habitat (e.g. Zambezi valley), it cannot as yet be used for black rhino conservation. The Zambezi valley alone once held more than 3 000 rhino, but today is down to less than 250, probably less.
This can over the long-term lead to a genetic bottle-neck within this particular population. The situation is even worse within smaller populations, and there are many of them. If Zambezi black rhino cells had been banked down just twenty years ago, then theoretically their gene diversity could quickly be returned to its former levels of 3 000 plus individuals.
One would only contemplate such a project once the appropriate cloning technology is developed for rhino and when their habitat is effectively secured. In the mean time it is important to bank down cell cultures so as to one day have the option to clone or not.