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. 2021 Oct 10;11(10):2925.
doi: 10.3390/ani11102925.

Genomic Regions Associated with the Position and Number of Hair Whorls in Horses

Diogo Felipe Pereira de Assis Lima  1 , Valdecy Aparecida Rocha da Cruz  1 , Guilherme Luís Pereira  2 , Rogério Abdallah Curi  2 , Raphael Bermal Costa  1 , Gregório Miguel Ferreira de Camargo  1
Affiliations

Genomic Regions Associated with the Position and Number of Hair Whorls in Horses

Diogo Felipe Pereira de Assis Lima et al. Animals (Basel). .

Abstract

The position and number of hair whorls have been associated with the behavior, temperament, and laterality of horses. The easy observation of whorls assists in the prediction of reactivity, and thus permits the development of better measures of handling, training, mounting, and riding horses. However, little is known about the genetics involved in the formation of hair whorls. Therefore, the aim of this study was to perform a genome-wide association analysis to identify chromosome regions and candidate genes associated with hair whorl traits. Data from 342 Quarter Horses genotyped for approximately 53,000 SNPs were used in an association study using a single-step procedure. The following traits were analyzed: vertical position of hair whorl on the head, number of whorls on the head, and number of whorls on the left and right sides of the neck. The traits had between one and three genomic windows associated. Each of them explained at least 4% of the additive variance. The windows accounted for 20-80% of additive variance for each trait analyzed. Many of the prospected genes are related to hair follicle growth. Some of these genes exert a pleiotropic effect on neurological and behavioral traits. This is the first indication of biological and physiological activity that might explain the association of hair whorls and temperament.

Keywords: Quarter Horse; SNP; behavior; hair follicle; temperament.

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Conflict of interest statement

The authors declare that there are no conflict of interest.

Figures

Figure 1
Figure 1
Official outline diagram from ABQM containing a graphic representation of the whorls’ position and number (authors’ own translation).
Figure 2
Figure 2
Manhattan plot of hair whorl position on the head of Quarter Horses. The y-axis indicates the proportion of variance explained by windows of 100 adjacent SNPs. The chromosomes are given on the x-axis.
Figure 3
Figure 3
Manhattan plot of hair whorl number on the head of Quarter Horses. The y-axis indicates the proportion of variance explained by windows of 100 adjacent SNPs. The chromosomes are given on the x-axis.
Figure 4
Figure 4
Manhattan plot of hair whorl number on the left side of the neck of Quarter Horses. The y-axis indicates the proportion of variance explained by windows of 100 adjacent SNPs. The chromosomes are given on the x-axis.
Figure 5
Figure 5
Manhattan plot of hair whorl number on the right side of the neck of Quarter Horses. The y-axis indicates the proportion of variance explained by windows of 100 adjacent SNPs. The chromosomes are given on the x-axis.
See this image and copyright information in PMC

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