The power of resolution of microsatellite markers and assignment tests to determine the geographic origin of cheetah ( Acinonyx jubatus) in Southern Africa

Abstract

Formerly found in 44 countries in Africa and Asia, cheetahs are currently confined to fragmented populations in 29 African countries, and remnant populations in Iran and Pakistan (Marker 2002). In southern Africa, cheetahs are at present found in Botswana, Namibia, South Africa and Zimbabwe. Trade in cheetah products and live export of cheetah from Namibia and Botswana is stringently controlled (CITES 1992). As a result, conservation authorities are constantly aware of potential illegal trade in cheetah over the Namibian and Botswana borders with South Africa. Where foul-play is involved, identification of source populations of confiscated animals will require implementation of identification techniques based on multilocus genotypes. Manel et al. (2002) demonstrated that genetic methods have high power of resolution to determine the geographic origin of population samples for sufficiently differentiated populations. Forensic science services for domesticated animals are well established in South Africa and have in recent years expanded to include game species, marine fish stock identification and ornamental fish (Grobler et al. 2005). In this paper, we describe the power of resolution of microsatellite markers and assignment tests to determine the geographic origin of cheetah (Acinonyx jubatus) confiscated in South Africa on suspicion of illegal import. Cheetah was formerly thought to be genetically highly monomorphic (presumably following a historic bottleneck), based on allozyme data (O’Brien et al. 1983). Subsequent studies (Menotti-Raymond and O’Brien 1993, 1995) have revealed genetic heterogeneity for microsatellite markers. This has been attributed to accumulated variation since the hypothetical bottleneck, resultant from the high mutation rates of microsatellite markers (Hedrick 1996). The presence of a moderate level of genetic diversity, comparable to other felids for some markers (Menotti-Raymond and O’Brien 1993), suggests that marker-based forensic identification in cheetah is feasible. Six cheetahs held on a farm without the required permits were confiscated by conservation authorities in the North West Province of South Africa. The farm is situated in an area known for a high incidence of illegal trade in cheetah, especially across the border with Botswana, and foul-play was therefore suspected. To assign the six unknown cheetah to their most likely region of origin, the animals were genotyped using microsatellite markers, and then compared to cheetah of known origin. The reference populations consisted of wild cheetah from Botswana, Namibia and the northwestern parts of South Africa. Geographical locations of ARTICLE IN PRESS