The Arabian oryx is an iconic antelope species native to desert and steppe areas of the Arabian Peninsula. It is the national animal of Jordan, Oman, the United Arab Emirates, Bahrain, and Qatar. Despite being a revered and admired species and a cultural symbol in the Gulf region, it became extinct in the wild in 1972 as a result of hunting and poaching. Luckily, there were many individuals held in captivity in zoos and private collections, and the success of captive breeding programs meant that small herds could be reintroduced into the wild.
In early 1982, the first herd was “rewilded” to a desert area in central Oman and, today, wild populations totaling 1,200 animals exist in several locations, mainly on the Arabian Peninsula. The Arabian oryx is the first animal species to be reclassified by the IUCN as “vulnerable” after being declared extinct in the wild. According to the IUCN Red List of Threatened Species, the species continues to face a high risk of extinction in the wild. Despite this, there are no formal breeding strategies in place to ensure the genetic diversity of the herds that remain.
To address this important issue, Professor Jaime Gongora of Sydney University, and his former PhD student Qais Al Rawahi and colleagues, conducted the first genomic analysis of Arabian oryxes in order to assess their genetic diversity and propose breeding strategies based on the results.
“There is more to the preservation of the Arabian oryx than conservation,” said Professor Gongora. “Historically and now, it has strong cultural significance in the Arabian Peninsula due to its unique physical features and strength, enabling it to live in harsh desert environments. It has even become a national icon in Saudi Arabia, Oman, Qatar, and the United Arab Emirates. That’s why we are working so hard to ensure it survives – for the oryx itself and to keep this cultural connection alive.”
Arabian oryxes are remarkable animals because of their ability to survive in the hot, dry desert environments where they occur. They can reduce their water loss through urine, feces and metabolic processes by up to 50 percent in dry conditions and have special anatomical features to keep the brain cool, even though the body temperature may rise above normal.
These antelopes can travel 75km a day, searching for food, and are known for their “sixth sense”: they can sense the location of incoming rain and move towards it to drink, as well as consume plants that thrive in moister conditions, like acacias. With a lifespan of between 15 and 20 years, they are a key food source for other species on the Arabian Peninsula including striped hyenas, Arabian wolves, and lynxes.
The researchers tested the DNA from 138 Arabian oryxes at the Al-Wusta Wildlife Reserve in Oman, where a herd of around 600 individuals is kept. They compared the results to 36 historical DNA samples from the Phoenix Zoo, from offspring of a herd established there in the 1970s. The experts studied the maternally inherited mitochondrial DNA and biparentally inherited single nucleotide polymorphisms – genetic variations used to identify species.
The results showed that the current gene pool of the Arabian oryx is reasonably diverse, despite the fact that there have been no coordinated breeding schemes to encourage genetic diversity. In fact, at 58 percent of the total diversity, the current-day sample was more genetically diverse than the historical ones. This is hardly surprising since the Phoenix Zoo’s original herd consisted of only nine individuals.
“This means that conservation strategies based on random mating could be reasonably successful,” said study lead author Professor Gongora. “This work in such an iconic species could serve as a benchmark for the long-term sustainability of other conservation programs. This includes those taking place at the Al-Wusta Wildlife Reserve involving the Sand Gazelle, the Mountain Gazelle and the Nubian Ibex.”
The research did identify the DNA of three ancestral groups among the sampled oryxes, but their genes were not evenly distributed across the current-day herds in the wildlife reserve. Based on this, the authors suggest a targeted breeding strategy whereby females should breed with males from the other genetic lineages. “To ensure the survival of the species, it’s not just about population size – it’s about genetic diversity,” emphasized Gongora.
Together with his colleagues, Professor Gongora is working with the Al-Wusta Wildlife Reserve to implement this strategy. The researchers also recommend that Arabian oryx genetic samples be stored in a biobank for future genetic analyses. In addition, biobanking of eggs and sperm samples could also be considered as a long-term insurance policy against the extinction of this species.
The study is published in the journal Royal Society Open Science.
By Alison Bosman, Earth.com Staff Writer