Study on Expression of Melanin-related Proteins in Yak Skins with Different Coat Colors

Background: The multiple coat colors of yaks are mainly determined by melanin synthesized by melanocytes. Comparing the amount and distribution of melanin and melanocytes in the skin of yaks with different coat colours has not yet been described; moreover, studying the expression of melanin-related proteins in the skin of yaks with different coat colors will help to further understand the molecular basis of the regulation of coat color in animals. This study observes the histomorphological structure of white, brown and black yak skin and investigates the expression of melanocyte markers MITF, SOX10, PMEL, TYRP1, DCT, MC1R and KIT, in white, brown and black yak skin. Methods: HE staining and transmission electron microscopy (TEM) were performed for histomorphological observation. Immunofluorescence analyses were performed to assess marker expression. Result: Our results showed that there was no melanin in the skin of white yaks; whereas the melanin formation process was not problematic in brown and black yaks and the formation of brown hair colour could be due to the low number of melanocytes and the fact that melanocytes were mostly early in differentiation.