Cheetah, Stalking by RyanTaylor1986 on Flickr.

Cheetah Acinonyx Jubatus - The fastest land mammal on earth. Prior to the 20th century they lived throughout Africa, Arabia and Asia. In 1900 there were over 100k. Now the population is estimated to be as low as 9k mainly in Africa, a few in Iran.

Taken at the Wildlife Heritage Foundation near Headcorn in Kent. This is a big cat sanctuary helping to protect the big cats from extinction.

Homozygosity and Inbreeding Depression in the Cheetah

Preservation of genetic diversity within declining populations of endangered species is a major concern in the discipline of conservation biology. 

The vulnerable cheetah, Acinonyx jubatus, exhibits relatively little genetic variability. Since the discovery of the cheetah’s relative homozygosity, this species has been frequently cited as an example of one whose survival may be compromised by the loss of genetic diversity.

The cheetah’s genetic uniformity is generally believed to be the result of an historical population bottleneck followed by a high level of inbreeding. Evidence offered in support of this hypothesis includes the cheetah’s present low level of genetic variability and symptoms of inbreeding depression in captive populations.

Carnivores exhibit significantly lower levels of genetic variation than other mammals, and several carnivores for which data are available exhibit lower levels of heterozygosity and polymorphism than the cheetah does.

Measures of fluctuating asymmetry do not support the hypothesis that the cheetah is suffering an increased level of homozygosity due to genetic stress. Many of the phenotypic effects attributed to inbreeding depression, such as infertility, reduced litter sizes, and increased susceptibility to disease, are limited to captive individuals and may be explained as physiological or behavioral artifacts of captivity.

In sum, the genetic constitution of the cheetah does not appear to compromise the survival of the species. Conservation efforts may be more effectively aimed at a real, immediate threat to the cheetah’s future: the loss of its natural habitat.

Source: Merola M. 1994. A reassessment of homozygosity and the case for inbreeding depression in the cheetah, Acinonyx jubatus: Implications for conservation. Conservation Biology 8(4):961-71.

Photo credit: ©Hendri Venter | Young Cheetah brothers in the Kgalagadi Transfrontier Park, South Africa.