Allele frequency of hereditary equine regional dermal asthenia in American Quarter horses in Brazil determined by quantitative real-time PCR with high resolution melting analysis.

This study investigates the frequency of a gene mutation causing a genetic disorder (HERDA) in American Quarter horses in Brazil. The research concluded that the HERDA allele and carrier rates were found to be 2.9% and 5.8% respectively.

Introduction

• The research focuses on Hereditary Equine Regional Dermal Asthenia (HERDA), a genetic disorder present in American Quarter Horses (AQH). HERDA leads to the skin becoming overly stretchy and fragile, which can result in wounds that are slow to heal.
• The disease is triggered by a c.115G>A missense mutation in the PPIB (peptidylprolyl isomerase B) gene. This means that there is a single nucleotide change in the gene’s DNA sequence that results in a different amino acid being incorporated, potentially resulting in a seriously compromised protein.

Research Method

• The team used a quantitative real-time PCR (polymerase chain reaction) with high-resolution melting analysis for the genotyping assay – this technique facilitated the precise detection of the gene mutation in the horses.
• PCR is a method widely used in molecular biology to make several copies of a specific DNA segment, enabling scientists to have a sufficient amount of DNA to study in detail.
• High-resolution melting (HRM) analysis is a technique employed post-PCR to differentiate DNA sequences based on their melting behavior, hence making it possible to detect minor sequence variations such as the c.115G>A
  missense mutation.

Results and Conclusion

• Upon using these precise tools, the study concluded that amongst Brazilian AQHs, the estimated frequency of the HERDA allele was 2.9%, with a carrier frequency of 5.8%.
• An allele is essentially a variant form of a given gene, occasionally resulting in different traits, such as diseases. In the context of this study, a carrier frequency refers to the number of horses carrying the specific PPIB gene mutation but not necessarily exhibiting signs of it.