Colour-sidedness in Gloucester cattle is associated with a complex structural variant impacting regulatory elements downstream of KIT

Colour-sidedness is a striking coat color pattern found in a number of cattle breeds, typically characterized by a white stripe that extends along the back, head and belly of the animal. This dominant phenotype is caused by two related translocations (Cs6 and Cs29) that alters a region downstream of the KIT gene. Gloucester cattle are native to the U.K. and are known for an unusual colour-sided pattern that does not extend to the head. We carried out whole genome sequencing of two Gloucester bulls as well as a colour-sided Irish Moiled, British White and Pustertaler Sprinzen to determine its molecular basis. We found that the Gloucester cattle also have a complex structural variant downstream of KIT, which overlaps the regions involved in Cs6 and Cs29. All three alleles potentially disrupt a number of putative regulatory elements downstream of KIT. These results confirm the recently published work focused on the Pinzgauer bread from Austria, a carrier of the same colour-sided pattern seen in Gloucester cattle. They also add additional information on the mechanisms of their formation as well as the putative regulatory elements impacted.