 |
|
CAS Colors of Chemistry
Black "tear-marks" streak from each eye down to the solemn mouth. This is how you distinguish spotted cheetahs from leopards or jaguars. Tear-marks are but one of many characteristics that make cheetahs unique among other Felidae. The only big cat that hunts during the day, the cheetah depends upon its sharp eye sight to spot prey and predators. The black streaks aid in reducing sun-glare. Cheetahs possess a smaller stature, less aggressive nature, and blunt, dog-like claws unable to lacerate. These are traits that recommend them as pets, but dont let their purr lull you into letting them lick your face. A few swipes from their raspy tongue can remove your skin. The fastest of all land animals for short spurts, cheetahs can go from 0 to 68 mph in 3.5 seconds. Extreme inbreeding has left cheetahs clones of one another. Scientists theorize that the cheetahs lack of genetic variation results from a demographic crash 10,000 years ago. A lack of genetic diversity, has meant that anthrax, prion-like AA amyloidosis, and other diseases caused by the stresses of captivity threaten their extinction.
Related Record from CAplus118: 252065 Dating the genetic bottleneck of the African cheetah. Menotti-Raymond, Marilyn; OBrien, Stephen J. Lab. Viral Carcinogen., Natl. Cancer Inst., Frederick, MD, USA. Proceedings of the National Academy of Sciences of the United States of America 1993, 90(8), 3172-6 (Eng). The cheetah is unusual among felids in exhibiting near genetic uniformity at a variety of loci previously screened to measure population genetic diversity. It has been hypothesized that a demog. crash or population bottleneck in the recent history of the species is causal to the obsd. monomorphic profiles for nuclear coding loci. The timing of a bottleneck is difficult to assess, but certain aspects of the cheetahs natural history suggest it may have occurred near the end of the last ice age (late Pleistocene, approx. 10,000 yr ago), when a remarkable extinction of large vertebrates occurred on several continents. To further define the timing of such a bottleneck, the character of genetic diversity for two rapidly evolving DNA sequences, mitochondrial DNA and hypervariable minisatellite loci, was examd. Moderate levels of genetic diversity were obsd. for both of these indexes in surveys of two cheetah subspecies, one from South Africa and one from East Africa. Back calcn. from the extent of accumulation of DNA diversity based on obsd. mutation rates for VNTR (variable no. of tandem repeats) loci and mitochondrial DNA supports a hypothesis of an ancient Pleistocene bottleneck that rendered the cheetah depauperate in genetic variation for nuclear coding loci but would allow sufficient time for partial reconstitution of more rapidly evolving genomic DNA segments. 149: 124414 Are cheetahs on the run from prion-like amyloidosis? Caughey, Byron; Baron, Gerald S. Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, Hamilton, MT, USA. Proceedings of the National Academy of Sciences of the United States of America 2008, 105(20), 7113-7114 (Eng). A review. The research of Zhang, B.; et al. (2008), entitled Fecal transmission of AA amyloidosis in the cheetah contributes to high incidence of disease, is reviewed with commentary and refs. 128: 46398 Skeletal muscle histology and biochemistry of an elite sprinter, the African cheetah. Williams, T. M.; Dobson, G. P.; Mathieu-Costello, O.; Morsbach, D.; Worley, M. B.; Phillips, J. A. Department of Biology, Earth and Marine Science, University of California, Santa Cruz, CA, USA. Journal of Comparative Physiology, B: Biochemical, Systemic, and Environmental Physiology 1997, 167(8), 527-535 (Eng). To establish a skeletal muscle profile for elite sprinters, the authors obtained biopsy samples from the vastus lateralis, gastrocnemius, and soleus muscles of African cheetahs (Acinonyx jubatus). The muscle ultrastructure was characterized by the fiber type compn. and mitochondrial vol. d. of each sample. Maximum enzyme activity, myoglobin content, and mixed fiber metabolite content were used to assess the major biochem. pathways. The results demonstrated a preponderance of fast-twitch fibers in the locomotor muscles of cheetahs; 83% of the total no. of fibers examd. in the vastus lateralis and nearly 61% of the gastrocnemius were comprised of fast-twitch fibers. The total mitochondrial vol. d. of the limb muscles was in the range of 2.0-3.9% for 2 wild cheetahs. Enzyme activities reflected the sprinting capability of the cheetah...
Additional Information
Updated: 1/26/2009 2:08:33 PM
|
