Detection of equine X chromosome mosaicism in a mare using an equine X whole chromosome painting probe (WCPP)–a case report.

The research article talks about a cytogenetic analysis carried out on an infertile mare with underdeveloped ovaries. The study detected an equine X chromosome mosaicism in the mare’s genome using a unique probe, notably, the equine X whole chromosome painting probe (WCPP).

Introduction and Study Background

• The infertile mare subjected to the research had hypoplastic ovaries, suggesting underdevelopment and likely the cause of infertility.
• The study aimed at performing an in-depth cytogenetic analysis to understand the root cause of the mare’s infertility.

Methodology

• The researchers used a technique known as Fluorescence in situ hybridisation (FISH) for the cytogenetic study. FISH offers benefits in cytogenetic analysis because it is a direct visual approach that helps detect genetic abnormalities like duplications, deletions, or translocations in the chromosomes.
• For the FISH analysis, they employed the equine X whole chromosome painting probe (WCPP). This probe helps paint out the entire X chromosome, highlighting any anomalies that may exist therein.
• The testing was performed on a chromosome preparation derived from the blood lymphocyte culture of the infertile mare.
• A high number of analysed spreads (235) was used, ensuring a broad and thorough analysis.

Findings

• X chromosome aneuploidy in mosaic form was diagnosed as a result of the study. Aneuploidy is a condition where a cell has an abnormal number of chromosomes, which, in mosaicism, may vary such that some cells show typical chromosome numbers, while others exhibit the abnormal count.
• The karyotype formula for the mare was found to be 63,X / 64,XX / 65,XXX, indicating three different cell lines with varying X chromosome count. This further confirmed the diagnosis of X chromosome mosaicism.
• The distribution ratio among the three cell lines was 15%, 82%, and 3%, respectively.

Discussion and Conclusion

• The use of the FISH technique with WCPP proved effective in detecting the genetic anomaly in the mare, further emphasizing its potential in such cytogenetic analyses.
• The research provides an expanded understanding of the genetic reasons behind infertility in horses, specifically mares, and paves the way for improved diagnostic strategies.