Coat Color Roan Shows Association with KIT Variants and No Evidence of Lethality in Icelandic Horses.

Katharina Voß,Georg Thaller,Julia Tetens,Doreen Becker

doi:10.3390/genes11060680

Katharina Voß, Georg Thaller + Show 2 more

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https://doi.org/10.3390/genes11060680

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Abstract

Roan (Rn) horses show a typical seasonal change of color. Their body is covered with colored and white hair. We performed a descriptive statistical analysis of breeding records of Icelandic horses to challenge the hypothesis of roan being lethal in utero under homozygous condition. The roan to non-roan ratio of foals from roan × roan matings revealed homozygous roan Icelandic horses to be viable. Even though roan is known to be inherited in a dominant mode and epistatic to other coat colors, the causative mutation is still unknown. Nevertheless, an association between roan phenotype and the KIT gene was shown for different horse breeds. In the present study, we identified KIT variants by Sanger sequencing, and show that KIT is also associated with roan in the Icelandic horse breed.

Highlights

The coat color roan (Rn) describes a mixture of white and colored hair on the body [1], while mane, tail, head and distal legs are not affected [2,3]
Similar color patterns, with white hair intermingling with colored hair, exist, e.g., rabicano or roaning/roaned [15], vanish roan caused by the leopard complex [21,22], Sabino [23] and other KIT-mutations [9], even though most of them have not been reported in the Icelandic breed so far
We demonstrated a significant association of KIT with roan coat color in the Icelandic horse

Summary

Introduction

The coat color roan (Rn) describes a mixture of white and colored hair on the body [1], while mane, tail, head and distal legs are not affected [2,3]. Due to the similar phenotype, it can potentially be confused with other coat colors, e.g. gray [2,4], though in contrast to gray horses that are born any solid color, true roan foals are born roan. Roan horses do not become progressively lighter in color as they age [2,3,4]. What is unique about the phenotype is the seasonal change of color: because of the undercoat hair’s being white, the horse0 s body appears silver gray to white when the covering coat is shed in spring and fall. The extent and amount of white hair can vary individually

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Conclusion