Genetics: How cats get their stripes

The formation of fur patterns, such as tabby, in domestic cats is determined by specific molecules in the developing embryo, a study in Nature Communications suggests. The findings provide insights into how identical skin cells can acquire different genetic signatures that later give rise to intricate patterns in hair colour, which are a defining feature of diversity in cats and many other mammals.

Previous research has shown that colour patterns in domestic cats appear during hair growth when groups of adjacent hair follicles produce different types of melanin pigment. However, the developmental process that determines whether a hair follicle produces black or yellow melanin remains unclear.

Gregory Barsh and colleagues studied skin samples from non-viable cat embryos at different stages of development, and analysed the genes of single cells and the proteins found in tissue sections. The authors observed that differences in embryonic gene expression determine the shape of the colour pattern produced later during hair growth. They suggest that a signaling molecule encoded by the gene Dickkopf 4 (Dkk4) plays a central role in this process and demonstrate that Dkk4 is mutated in cats with ticked patterns such as Abyssinian or Servaline Savannah.

Although this investigation was focused on domestic cats, Barsh and co-authors suggest that these findings may apply to colour pattern formation in leopards, tigers, and other mammals.