Related Experiment Video
Updated: Apr 15, 2026

Development of an in vitro model system for studying the interaction of Equus caballus IgE with its high-affinity receptor FcεRI
Published on: November 1, 2014
HERDA-associated variant in bull-catching (vaquejada) Brazilian Northeastern bull-catching Quarter Horses
A M Caceres1, L M S Sperandio1, N A C A Alvarenga1
1Department of Veterinary Clinical Science, School of Veterinary Medicine and Animal Science, São Paulo State University (UNESP), Botucatu, São Paulo, 18618-681, Brazil.
Background:
Bull-catching (vaquejada) accounting for approximately 13% of sport horses in Brazil. Genetic screening has enabled strategies to reduce the spread of inherited disorders, including Hereditary Equine Regional Dermal Asthenia (HERDA), a major skin disease included in the Six Panel required for registration by the Brazilian Quarter Horse Breeders Association. Although the HERDA-associated variant has been extensively studied in other disciplines, it had not been evaluated in Bull-catching Quarter Horses (QH).
Aims/Objectives:
The present study aimed to determine the allele frequency of the pathogenic variant associated with HERDA in the Brazilian Northeastern bull-catching Quarter Horse population.
Methods:
This study investigated the HERDA allele frequency in 141 Bull-catching QH from Northeastern Brazil using Sanger sequencing.
Results:
Eight horses were heterozygous, resulting in an allele frequency of 0.028, the third highest among Brazilian QH disciplines. Assuming random mating, HERDA is expected to affect one foal per 1,000 births, with 58 carriers.
Conclusion:
Given nonrandom breeding practices, the actual impact may be higher, reinforcing the importance of mandatory genotyping to guide breeding decisions and reduce economic loss and animal suffering.
Related Concept Videos
Genetic Lingo
Incomplete Dominance
Heritability
Lethal Alleles
Lucien Cuénot discovered lethal alleles in 1905 while studying the inheritance of coat color in mice. The agouti gene is responsible for the color of the coat in mice. This gene codes for an agouti-signaling protein, which is responsible for melanin distribution in mammals. The wild-type allele gives rise to gray-brown coat color in mice, while the mutant allele gives rise to yellow coat color. In addition to coat color, the agouti gene is associated with the yellow...
Cardiomyopathy III: Hypertrophic Cardiomyopathy
Hardy-Weinberg Principle

