Coat colour can preserve older genetic history

Research published in the Journal of Heredity’s March 2020 issue investigated white markings and nose pigmentation in North American yak. Jessica Petersen and colleagues identified a KIT-region haplotype associated with white coloration and an MC1R haplotype associated with black nose pigment. A haplotype is a set of linked genetic variants inherited together.

The white-associated KIT region spanned 388 kilobases and behaved in a semi-dominant manner in the studied population. The black-nose association involved two protein-changing MC1R variants. These results help explain why recognizable colour differences can follow inherited patterns rather than being purely cosmetic variation.

Some sequences resembled cattle haplotypes, but none of the cattle examined carried either exact yak colour-associated haplotype. The researchers therefore suggested that introgression happened before these yak reached North America. That finding cautions against treating a white marking as proof of a recent cattle cross. Colour genetics can inform mating expectations, while broader ancestry and parentage questions still require appropriate records and genetic evidence.