Thursday, October 31, 2013

[Mammalogy / Genetic • 2012] Specifying and Sustaining Pigmentation Patterns in Domestic and Wild Cats | Genetic Study reveals How the Cheetah got its Stripes


The spots displayed by a typical cheetah (standing), compared with the blotched pattern of king cheetahs
[photo: The Ann van Dyk Cheetah Preserve]

Abstract
Color markings among felid species display both a remarkable diversity and a common underlying periodicity. A similar range of patterns in domestic cats suggests a conserved mechanism whose appearance can be altered by selection. We identified the gene responsible for tabby pattern variation in domestic cats as Transmembrane aminopeptidase Q (Taqpep), which encodes a membrane-bound metalloprotease. Analyzing 31 other felid species, we identified Taqpep as the cause of the rare king cheetah phenotype, in which spots coalesce into blotches and stripes. Histologic, genomic expression, and transgenic mouse studies indicate that paracrine expression of Endothelin3 (Edn3) coordinates localized color differences. We propose a two-stage model in which Taqpep helps to establish a periodic pre-pattern during skin development that is later implemented by differential expression of Edn3.




A leopard with distinctive stripes that was photographed from Parambikulam Tiger Reserve in Palakkad district of Kerala, India

Kaelin CB, Xu X, Hong LZ, David VA, McGowan KA, Schmidt-Küntzel A, Roelke ME, Pino J, Pontius J, Cooper GM, Manuel H, Swanson WF, Marker L, Harper CK, van Dyk A, Yue B, Mullikin JC, Warren WC, Eizirik E, Kos L, O'Brien SJ, Barsh GS, Menotti-Raymond M. 2012. Specifying and Sustaining Pigmentation Patterns in Domestic and Wild Cats. Science. (6101): 1536-41.


Genetic Study reveals How the Cheetah got its Stripes

Feral cats in Northern California have enabled researchers to unlock the biological secret behind a rare, striped cheetah found only in sub-Saharan Africa, according to researchers at the Stanford University School of Medicine, the National Cancer Institute and HudsonAlpha Institute for Biotechnology in Huntsville, Alabama. The study is the first to identify a molecular basis of coat patterning in mammals.

The scientists found that the two felines share a biological mechanism responsible for both the elegant stripes on the tabby cat and the cheetah's normally dappled coat. Dramatic changes to the normal patterns occur when this pathway is disrupted: The resulting house cat has swirled patches of color rather than orderly stripes, and the normally spotted cheetah sports thick, dark lines down its back.

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