Friday, March 4, 2016

Chewbaaka Finishes the Race to Complete the Cheetah Genome

Photo by David Newton

Cheetah, one of the poster children of the Savannah, have been in trouble for quite some time. With dwindling numbers in the wild and difficulty breeding in captivity, scientists have been studying not only the behavior but also the genetics of cheetah for insight on how to help the continuation of this species. Behaviorally, cheetah could be called complicated, due to their unique behaviors. While these behaviors are interesting to study, some of the behavior is detrimental to their breeding processes. Females in the wild and captivity are highly selective in choosing a mate. With the help of the Species Survival Plan (SSP), many zoos raise various exotic animals with the hope of successful breeding in the future. Cheetah are especially difficult to breed due to the picky nature of females linked to their love for solitude. While working with cheetah at a zoo, other keepers warned me that female cheetah are so particular that it is not uncommon for multiple males to be introduced to a female before she chooses a mate. Then, even after a companion is chosen, it is also not unlikely for the pair to successfully produce no offspring, if she mates with him at all. Behaviorally, cheetah have difficulty mating, however there are genetic odds stacked against them too.

Research in big cats can sometimes be difficult due to their short lifespan. Typically big cats don't live much more than 7 years, due to the high rates in cancer and other complications they suffer from in aging. An orphaned cheetah from Namibia was rescued by the Cheetah Conservation Fund (CCF) in 1995. Little did the CCF know, he would live for a surprising 16 years! Named Chewbaaka, this cheetah was able to help complete the genome for his species. With the complete genome of cheetah complete, scientists have been able to further research the genetic obstacles that are preventing cheetah from thriving as a species. The completion of the cheetah genome revealed an unsettling fact, that cheetah show very little diversity in terms of genetics. Prior to reading this article, I did not know that work was being done to complete genomes outside of the human species and I was very surprised to learn about this. This also led me to other very interesting articles that further dissected the issue.

As a result of Chewbaaka's contribution to genetics, scientists decided to examine the lack of overall genetic variation among various cheetah.  With the major lack of diversity, cheetah suffer from an array of issues including "elevated juvenile mortality, extreme abnormalities in sperm development, difficulties until recently in achieving sustainable captive breeding, and increased vulnerability to infectious disease outbreaks". Unfortunately the effects of little genetic variation has resulted in traits that inhibit the cheetah's ability to produce viable offspring at numerous stages of life, from fertilization to surviving infancy. Due to the selective nature of female cheetah, inbreeding has become incredibly common among cheetah, creating the issue within the genetic variation of the entire species. Thankfully, there are currently programs working to try to increase the odds of cub production and survival of numerous big cats. While working with cheetah, I also learned of how the SSP helps zoos and the breeding of endangered animals within them. With the problems of genetic diversity in mind, the SSP matches animals who are not closely related, with favorable traits that would hopefully lead to successful offspring. In doing this, the SSP attempts to increase variation within the available gene pool of captive cheetah and other animals to hopefully increase success in breeding in the future. I think that this will greatly improve the status of success of cheetah in captivity, however it would be very difficult to replicate in the wild. 

No comments:

Post a Comment