07.07.2022: With only 7,100 animals living in the wild, the cheetah is one of the most endangered mammals in the world, with some subspecies acutely threatened with extinction. But the low number of individuals alone is not the only problem. A recently published genomic analysis conducted by an international team of researchers led by the Research Institute of Wildlife Ecology at Vetmeduni Vienna reveals an extremely low genome-wide heterozygosity, which denotes the possession of two different forms of a particular gene inherited from each parent. The study also confirmed the division of East African and Southern African cheetahs into two distinct subspecies.
The study, published in Molecular Ecology, presents the most comprehensive genome-wide analysis of cheetah (Acinonyx jubatus) phylogeography and conservation genomics to date, compiling samples from nearly the entire current and past species range. The researchers show that cheetah phylogeography – the study of past and present geographic distributions of genealogical lineages – is more complex than previously thought, and that East African cheetahs (A. j. raineyi) are genetically distinct from Southern African individuals (A. j. jubatus), justifying their recognition as a distinct subspecies.
High inbreeding and low heterozygosity in critically endangered subspecies
The study’s final author, Pamela Burger from the Research Institute of Wildlife Ecology at Vetmeduni Vienna, explains the new findings: “We found strong genetic differentiation between all classically recognised subspecies, thus refuting earlier findings that cheetahs show only little differentiation. The strongest differentiation was observed between the Asiatic and all the African subspecies.”
The researchers detected high inbreeding in the critically endangered Iranian (A. j. venaticus) and North-West African (A. j. hecki) subspecies. According to Stefan Prost from the Research Institute of Wildlife Ecology, this yields the following overall picture: “Along with snow leopards, cheetahs have the lowest genome-wide heterozygosity of all the big cats. This further emphasizes the cheetah’s perilous conservation status.”
Important findings for cheetah conservation
According to the researchers, the results of their study provide novel information on cheetah phylogeography that can support evidence-based conservation policy decisions to better protect this critically endangered species. This is especially relevant given ongoing and proposed translocations of cheetahs across subspecies boundaries and the increasing threat of illegal trafficking. Individual subspecies such as A. j. venaticus, which is only found in Iran and is represented by fewer than 50 individuals, require rapid and efficient conservation measures.
Cheetahs help ensure healthy functioning of the ecosystems they live in
Apex predators such as the cheetah play an important role in maintaining ecosystem balance. Standing at the top of the food chain, they contribute significantly to preserving natural and healthy habitats. Due to biodiversity loss and global environmental change, however, many large carnivores are threatened with extinction. This can have far-reaching effects on ecosystems, such as an uncontrolled increase in wild herbivores, which in turn has negative impacts on vegetation regeneration. The cheetah is heading for an uncertain future. Threatened by habitat loss, human-wildlife conflict and illegal trafficking, only about 7,100 individuals remain in the wild.
The article Genomic Analyses Show Extremely Perilous Conservation Status of African and Asiatic Cheetahs (Acinonyx jubatus)” by Stefan Prost, Ana Paula Machado, Julia Zumbroich, Lisa Preier, Sarita Mahtani-Williams, Rene Meissner, Katerina Guschanski, Jaelle C. Brealey, Carlos Rodríguez Fernandes, Paul Vercammen, Luke T. B. Hunter, Alexei V. Abramov, Martin Plasil, Petr Horin, Lena Godsall-Bottriell, Paul Bottriell, Desire Lee Dalton, Antoinette Kotze and Pamela Anna Burger was published in Molecular Ecology.