Development of a 17-Plex of Penta- and Tetra-Nucleotide Microsatellites for DNA Profiling and Paternity Testing in Horses.
Authors: Luttman Andrea M, Komine Misa, Thaiwong Tuddow, Carpenter Tyler, Ewart Susan L, Kiupel Matti, Langohr Ingeborg M, Venta Patrick J
Journal: Frontiers in veterinary science
Summary
# Editorial Summary Tetranucleotide and pentanucleotide microsatellites (tetraSTRs and pentaSTRs) offer superior technical properties for equine DNA profiling compared to the dinucleotide markers (diSTRs) currently used as standard, yet horses contain far fewer suitable tetra- and pentanucleotide repeats than other species, making their discovery and development challenging. Researchers identified and validated a 17-plex panel of tetra- and pentaSTRs plus an amelogenin sex marker by screening across 128 horses from 16 breeds, achieving strong genetic variability with average observed heterozygosity of 0.66 and expected heterozygosity of 0.72, alongside a probability of identity within breeds of 1.1 × 10⁻¹¹ and between siblings of 1.5 × 10⁻⁵. The new panel demonstrated substantially lower stutter artefacts (6.9% average) compared to the >30% typically produced by conventional diSTR markers, a reduction that meaningfully improves allele calling accuracy and reliability in parentage and individual identification work. These markers will enable development of standardised allelic ladders, facilitating cross-laboratory data sharing and consistency—particularly valuable for breed registries, stud book management, and investigations requiring robust genetic confirmation. Whilst this panel was initially developed during research into Friesian megaesophagus genetics, the refined methodology offers equine professionals a more dependable molecular tool for routine profiling and paternity verification across all breeds.
Read the full abstract on PubMed
Practical Takeaways
- •This improved microsatellite panel offers more accurate DNA profiling and paternity testing in horses compared to current dinucleotide-based methods, with lower technical error rates that should improve reliability of genetic testing results
- •The reduced stutter artifacts (6.9% vs >30%) mean cleaner, more interpretable DNA profiles that could facilitate cross-laboratory comparisons and standardization of equine genetic testing protocols
- •While this study focused on genetic tool development rather than clinical diagnosis, the refined methodology may enable future identification of heritable conditions like megaesophagus in breed populations
Key Findings
- •A 17-plex panel of tetra- and pentanucleotide microsatellites was successfully developed for equine DNA profiling with average observed heterozygosity of 0.66 and expected heterozygosity of 0.72
- •Stutter artifacts averaged 6.9% across all markers, substantially lower than the >30% typically observed with dinucleotide STRs currently used in horses
- •Probability of identity within breeds was at least 1.1 × 10⁻¹¹, providing high discrimination power for paternity testing
- •Panel was validated across 128 horses representing 16 breeds with consistent genetic variability, though no causative genes for Friesian megaesophagus were identified