First sex modification case in equine cloning.
Authors: Suvá Mariana, Arnold Victoria Helga, Wiedenmann Elisabet Astrid, Jordan Roberto, Galvagno Emanuel, Martínez Marcela, Vichera Gabriel Damián
Journal: PloS one
Summary
# Editorial Summary: Sex-Reversed Cloning in Horses Somatic cell nuclear transfer (SCNT) typically produces clones genetically identical to their donor, preserving all chromosomal characteristics including sex; however, this research documents the first recorded case of a female foal cloned from a male donor animal in equines. From 16 blastocysts generated through a single SCNT procedure and implanted in eight recipient mares, two viable clones were born—one genetically male and one female—with microsatellite analysis confirming identical DNA profiles across 15 equine markers. Cytogenetic and fluorescence in situ hybridisation investigation revealed the female offspring possessed a 63,X karyotype rather than the expected 63,XY, indicating spontaneous loss of the Y chromosome during development, which was further confirmed through PCR detection of X-linked markers and absence of Y-linked genetic material. Whilst the mechanism triggering this chromosomal loss remains unclear, and mosaicism was ruled out through analysis of both blood and skin samples, the occurrence suggests SCNT may offer unexpected opportunities for sex modification in horses. For equine practitioners and breeders, these findings open intriguing possibilities for managing genetic diversity in endangered bloodlines, developing novel breeding protocols, and potentially addressing specific sporting or breeding objectives, though considerably more research is required to understand and reliably control this phenomenon.
Read the full abstract on PubMed
Practical Takeaways
- •Sex reversal during equine cloning is possible through spontaneous chromosome loss during SCNT, expanding potential breeding and preservation applications
- •Genetic verification by microsatellite analysis and cytogenetic profiling is essential when unexpected sex phenotypes occur in cloned horses
- •This technique may offer novel opportunities for endangered breed preservation and specialized breeding programs, though underlying mechanisms require further investigation
Key Findings
- •First reported case of female foal cloned from male nuclear donor via SCNT, with identical genetic profiles confirmed by 15-marker microsatellite panel
- •Cytogenetic analysis revealed 63,X chromosome set (monosomy X) in female clone due to spontaneous Y chromosome loss
- •PCR confirmed presence of X-linked markers and complete absence of Y-linked markers in sex-reversed foal
- •Chromosomal constitution identical in blood and skin samples, ruling out somatic mosaicism as explanation for sex reversal