Kaelin CB, Xu X, Hong LZ, et al. Specifying and sustaining pigmentation patterns in domestic and wild cats. Science. 2012; 337: 1536-41.
Mackerel versus blotched is the heritable variation of tabby markings in domestic cats (Felis catus). There are two features to tabby markings:
1) A light background component in which individual hairs have extensive light bands.
2) A superimposed darker component in which hairs have little or no banding. The dark component is organized into narrow vertical stripes with a constant and regular spacing in mackerel cats.
In cats with the blotched pattern, the dark component is expanded into a less organized structure with wide whorls. The authors believe the similar range of patterns in domestic cats suggests a mechanism whose appearance can be altered by selection. They identified the gene responsible for the tabby pattern variation in domestic cats. The gene is labeled as transmembrane aminopeptidase Q (Taqpep) that encodes for a membrane-bound metalloprotease. It was located by association mapping in feral cats from Northern California where they initially genotyped 58 SNPs in 8 blotched and 9 mackerel cats.
By performing analysis in 31 other felid species, they also identified Taqpep as the cause of the rare king cheetah phenotype where spots coalesce into blotches and stripes. Additional studies found that paracrine expression of Endothelin3 (Edn3) coordinates localized color differences. Further studies of color pattern in domestic-wild cat hybrids may offer opportunities in understanding complex color markings and how felids acquire their color patterns. [VT]
See also: Eizirik E, David VA, Buckley-Beason V, et al. Defining and mapping mammalian coat pattern genes: multiple genomic regions implicated in domestic cat stripes and spots. Genetics. 2010; 184: 267-75. [free full text article]