Kit基因对白马被毛褪色的影响

Effects of Kit gene on coat depigmentation in white horses

马毛色是品种鉴定和个体识别的重要依据,也是制定育种方案时必须考虑的重要性状之一。因此,研究马被毛褪色已成为当今国际马毛色研究领域的重要内容,试图弄清导致马被毛褪色的真正机理。目前已经发现,许多马种被毛褪色表型个体中3号染色体上的kit基因存在不同的显著突变。研究结果表明马kit基因的正常表达与否与表皮中黑色素细胞及黑色素的形成密切相关,从而控制是否出现褪色表型。然而,研究证明在不同马种间褪色表型个体在该位点上出现的突变存在着较大的种间差异。具有被毛完全褪色表型的马群非常少见,只是偶尔见于有些马种,但在内蒙古锡林郭勒盟西乌珠穆沁旗生存着较大数量的被毛褪色表型个体,被称为蒙古白马。然而,造成其被毛褪色的机理还没有得到证实,有趣的是至今为止在蒙古白马kit基因的21个外显子中还没有发现任何典型突变。因此,文章对近些年国际上对马被毛褪色的分子研究进展做一比较系统的综合叙述,为蒙古白马毛色形成的机理研究奠定基础,为今后的马匹毛色研究及其育种工作提供有价值的参考依据。

Coat color of horse is an important basis for both species identification and individual recognition and is also one of the important references traits for breeding.Therefore,the research on the mechanism of coat fading has become an important part of horses’ coat color study.It has been found that the white phenotype is closely related to the mutation of kit gene,which is located on chromosome 3.Investigated results showed that the formation of the epidermal melanoblast and melanin relies on the expression of kit gene,which determines the presence of white phenotype.Nevertheless,studies results have shown that the mutation of kit gene in the white horse exhibited significant differences among species.Horses that the coat color completely faded are very rare and are found occasionally in a few species.However,a larger number of horses that coat color completely faded,called Mongolian white horse,are found in West Ujimqin,Xilin Gol League,Inner Mongolia.Therefore,genetic mechanism of color fading in Mongolian white horses is still not clear.No typical mutations have been observed in 21 exons of kit gene in Mongolian white horse.This paper summarized recent international studies on molecular mechanism of color fading and tried to lay the foundation for the study of formation mechanism of Mongolian white horse.The aim of this review is to provide some valuable references to horses coat color research and breeding.