Sunday, March 10, 2013

Impact of a Genetic Bottleneck on Cheetahs


Today it is well known that, like many other species, Cheetahs are current residents of the endangered species list. As the number of surviving individuals in a species begins to drop, a  decline also occurs in the genetic variation of the species. This is one of the significant challenges faced by breeding programs as they try and maintain genetic variation with a limited number of available individuals.

It is estimated that Cheetahs experienced a genetic bottleneck around 10,000-12,000 years ago. This occurrence,  in addition to their current decline in numbers, has had significant impact upon the species genetic variation.

In the paper, Genetic Basis for Species Vulnerability in the Cheetah, the genetic similarity between Cheetahs is investigated. Multiple studies were performed to test for similiarity including examining the high occurrence of malformed sperm in both captive and wild Cheetahs. Another test involved small skin grafts being performed in order to determine the histocompatibility between unrelated Cheetahs. How long it takes for a rejection to occur indicates how similar two individuals immune systems are. Many of the Cheetahs failed to have rapid rejections, and only a couple showed signs of long term rejection. This indicated a level of similarity between immune markers that caused the immune system to fail at recognizing the Cheetah's own cells versus those of another Cheetah.

This level of genetic similarity presents reproductive challenges for the Cheetah, as well as increased susceptibility to disease. Many Cheetahs face high infant mortality rates, in addition to other issues. However, behavioral factors also play a role in the success of Cheetah reproduction, so it is possible to raise breeding success rates. Many breeding programs underway are working to preserve the remaining genetic variation of the Cheetah, as well as increase the species number. After all, who could resist wanting to protect those adorable fuzzy babies!

In addition to the article, more information about Cheetahs may be found at:

http://animals.howstuffworks.com/endangered-species/endangered-cheetah-info.htm

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