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A First: Knocking the spots off your cheetah

By Dave Armstrong - 23 Sep 2012 9:59:22 GMT
A First: Knocking the spots off your cheetah

King cheetah shows the spots of this rare variety joined together into stripes on the rear and shoulder while other spots can be seen joining up in a circle - King cheetah image; Credit: © Shutterstock

There are spotted leopards and striped tigers in the wild, and there are moggies that match their black, striped, tawny or spotted patterns in your home. Some tabbie cats have long irregular swirls which are identified genetically as "blotches." Almost unknown in most wild species, the king cheetah was identified as having them along with a tiny wild cat called the black-footed cat (Felix nigripes.)

The transmembrane-aminopeptidase gene (Taqpep for short) is the first gene found to influence the coat patterns of mammals. It is a recessive that creates the phenotype when gained from each parent to cause cheetah's spots to coalesce into the characteristic king cheetah stripes or blotches.

Christopher B. Kaelin, Xiao Xu, et al from a range of American and African universities have produced an interesting paper, published in the journal Science, to investigate the coat genetics of all cat species, with reference to this blotched patterning from both tabby cats and king cheetahs.

One of the pieces of evidence is illustrated by the family tree of these captive cheetahs. It positively shows that the gene controlling blotches in cheetahs is a recessive. This means that two copies of it are required, one from each parent, as you can see for example in the bottom right hand corner where the 7 kittens from the cross should give a 1:1 ratio (It is almost exactly given with a 3:4 split!)

King cheetah sightings

Credit: © Science Journal

Above: (Left) King cheetah sightings have been restricted to a small (grey-colored) region that includes the Northeast corner of South Africa and parts of Botswana and Zimbawe. (Right) The K977Nfs110 mutation is completely linked to the king cheetah pattern under a model of autosomal recessive inheritance with complete penetrance. Genotype results are shown for 32 captive animals from the DeWildt pedigree (non-mutant, +, or mutant, fs), and reveal that the mutation was introduced into the DeWildt pedigree by 3 captured animals (1-3). The animal from Northern California (4) is also derived from the DeWildt pedigree; dashed lines indicate 5 generations in which no king cheetahs were observed.

Pattern phenotype of F. nigripes

Credit: © Science Journal

Above: Pattern phenotype of F. nigripes, which resembles the atypical swirled pattern observed in domestic cats (Felis catus pic is the domestic cat) that carry the T139N allele

The Taqpep gene also transmogrifies domestic cat coats into a swirled, striped appearance and influences many members of the Felidae family to create diverse species characteristics and those varieties we all admire in our domestic species. The tabby cat we all know got its spotting pattern from this gene.

Mutation of a single gene causes stripes to become blotches, and spots to become stripes," said Greg Barsh, Professor of Genetics at Stanford University. Here is a distinct species (above) with the swirl gene evident called Felis nigripes. It comes from the southern African savannah. Known as the black-footed cat, it's a vulnerable species and in Appendix I of CITES. It's also the smallest cat in Africa (only 1.6kg.)

cheetah

And just in case you're yawning with boredom, here is the original fastest spotty animal on earth getting ready for another sprint. Compare with the king cheetah at the top - Cheetah image; Credit: © Shutterstock

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Topics: Wildlife