Leopards can’t change their spots? Cheetahs can30/09/2012 15:29:12 How the cat got his blotches
September 2012. As any cat lover knows, distinct patterns of dark and light hair colour are apparent not only in housecats but also in their wild relatives, from cheetahs to tigers to snow leopards. Researchers at the HudsonAlpha Institute for Biotechnology and Stanford University, along with colleagues around the world, have reported new genetic findings that help to understand the molecular basis of these patterns in all felines.
A so-called "mackerel tabby" cat has dark tiger stripes, which coalesce into swirls and blotches in a "classic tabby" cat. Like other periodic natural patterns such as stripes on a zebra or spinal bones and vertebra, the origin of these repetitive structures is an unsolved mystery. "Until now, there's been no obvious biological explanation for cheetah spots or the stripes on tigers, zebras or even the ordinary house cat," said Gregory Barsh, M.D., Ph.D., faculty investigator at HudsonAlpha and emeritus professor of genetics at Stanford University, one of the senior authors of the study.
How do cells know they are in a stripe?
Their examination of genes expressed in dark versus light hair cells revealed that patterned markings are due to variations in another gene, Edn3, being expressed at high levels in the darkly coloured hair cells. The researchers thus suggest that the Taqpep gene helps to establish either a periodic pattern for stripes or a spotted or blotched pattern, by determining the level of Edn3 expressed in each skin area at an early stage of the cat's development.
According to Barsh, discovery of new genetic pathways and mechanisms is the foundation for understanding the blueprint encoded in any genome, including humans. Studies with fruit flies and roundworms have revealed principles that govern how cancer cells live and die, he noted. "Uncovering new biologic principles in animals that are more closely related to humans, like cats, dogs and laboratory mice, may reveal unexpected insights with far-reaching implications for human biology and disease," he added.
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