The cream dilution gene, responsible for the palomino and buckskin coat colours, maps to horse chromosome 21.

The research explores the genes responsible for determining the coat colours palomino and buckskin in horses, specifically pointing out their location on horse chromosome 21.

Study Overview

• The study aimed to pinpoint the location for the genes specifically contributing to the coat colours buckskin and palomino in horses. These genes are often referred to as the cream dilution gene or the C locus.
• Initial results found linkage between what researchers believed to be the cream dilution variant of the C locus (Ccr) and a marker on horse chromosome 21 labelled as HTG10.

Detailed Data and Analysis

• Ensuing the preliminary results, the researchers investigated horse chromosome 21 further in order to confirm their initial findings. This also aided in the development of a small group of markers linked to the Ccr gene.
• Their efforts led to a significant improvement in the clarity of previously-reported linkage maps for horse chromosome 21.
• This facilitated in the development of an unambiguous linkage analysis map showing the order of marker and gene locations in relation to the Ccr gene on the chromosome. The map order provided was: SGCV16-(19.1 cM)-HTG10-(3.8 cM)-LEX60/COR73-(1.3 cM)-COR68-(4.5 cM)- Ccr-(11.9 cM)-LEX31.

Comparative Findings

• The researchers used comparative and synteny data to suggest that the horse’s C locus does not correspond to the tyrosinase gene (TYR). This contradicts previous assumptions that the TYR gene could be responsible for the coat colour of the horses. Thus, opening new insights and further question for the genetic makeup determining horse’s coat color.