Volume: 5, 2026
5th International PhD Students’ Conference at the University of Life Sciences in Lublin, Poland:
ENVIRONMENT – PLANT – ANIMAL – PRODUCT
Abstract number: A036
DOI: https://doi.org/10.24326/ICDSUPL5.A036
Published online: 22 April 2026
Identification of the crypto-tobiano coat pattern in the Hucul horse population using fluorescent in situ hybridization
Zuzanna Tarasek1, Bogusława Długosz1, Barbara Jaklińska2 and Monika Bugno-Poniewierska*1
1 Department of Animal Reproduction, Anatomy and Genomics, Faculty of Animal Breeding and Biology, University of Agriculture in Krakow
2 Hutsul Horse Stud Farm “Gładyszów” Regietów 28, 38-315 Uście Gorlickie
* Corresponding author: monika.bugno-poniewierska@urk.edu.pl
Hucul horses are one of the oldest primitive horse breeds included in the genetic resources conservation program in Poland. According to the breed standard, the accepted coat colors are bay, mouse dun, piebald, buckskin, and black. Unlike piebald horses, individuals with white markings on the head or limbs should be eliminated from breeding, as they do not meet the breed standard.
The characteristic pattern of white patches in piebald horses, known as tobiano, includes partially white limbs, a white streak in the mane and/or tail, and dark markings on the head.
The minimal tobiano pattern, known as crypto-tobiano, may be mistaken for ordinary white markings, which can lead to the unjustified elimination of genetically valuable individuals. The crypto-tobiano coat pattern is associated with the dominant TO allele and a paracentric inversion on chromosome 3 (ECA3q).
Coat color assessment is mainly based on phenotype, and in doubtful cases, molecular testing using the RFLP-PCR method or cytogenetic analysis using FISH (fluorescence in situ hybridization) is recommended.
The aim of this study was to apply the FISH technique to identify the ECA3(q13:q21) inversion in the chromosomes of Hucul horses with a minimal tobiano pattern. The research material consisted of chromosome preparations from peripheral blood lymphocytes of five horses from a stud farm in Gładyszów. Fluorescence in situ hybridization using probes specific to the CLOCK gene (labeled with digoxigenin) and the PDGFR gene (labeled with biotin) demonstrated the presence of the inversion in a heterozygous form in all individuals.
The results confirmed the usefulness of FISH as an effective diagnostic method for detecting the genetic basis of crypto-tobiano, which enables the preservation of genetically valuable individuals that would otherwise be excluded from breeding without genetic testing.
Keywords: crypto-tobiano; FISH; horse; Hucul horse; inversion
How to cite
Tarasek Z., Długosz B., Jaklińska B., Bugno-Poniewierska M., 2026. Identification of the crypto-tobiano coat pattern in the Hucul horse population using fluorescent in situ hybridization. In: 5th International PhD Students’ Conference at the University of Life Sciences in Lublin, Poland: Environment – Plant – Animal – Product. https://doi.org/10.24326/ICDSUPL5.A036