Oral communication, PS4 / C42

Official XXIst International Pigment Cell Conference website - 21-24 Sept 2011, Bordeaux - France | updated: September 04 2011

Genomics of pattern: from Akitas to Zebras

Stripes and spots in mammals are a fascinating character thought to be important for camouflage and species recognition, but the genetic basis for pattern formation and pattern variation remains unknown. In nature, the remarkable diversity of color patterns is exemplified by the variation displayed among the 36 extant wild cat species. We demonstrate the utility of a forward genetics approach in domestic cats that takes advantage of emergent genomic resources, genomic partitioning, and next generation sequencing to fine map and to clone pigmentation patterning genes. Using this approach, we find that at least one variation in pattern type is caused by recessively inherited loss-of-function in a gene conserved among all vertebrates, and whose identity is consistent with a theoretical reaction-diffusion system first proposed by Alan Turing more than 50 years ago. A mutation in the same gene causes a characteristic wild felid phenotype. We also developed a highly sensitive and robust methodology—EcoP15I-tagged Detection of Gene Expression, or EDGE—that is suitable for detecting and comparing gene expression among tissues from animals for whom fully assembled and annotated genomes do not yet exist. We carried out an EDGE analysis of patterned skin from dogs (yellow and black brindled stripes), cheetahs (yellow and black spots), and zebras (white and black stripes). In brindled dogs, the striping pattern is caused by a segmental duplication that leads to gene silencing, and our results suggest that epigenetic alterations in gene expression are confined to the duplicated segment. In zebras, the striping pattern is limited to hair rather than skin, and our results indicate that alterations in hair color are accompanied by alterations in hair structure.

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