Uncovering the Mysteries of Genomic Imprinting in Horses and Hybrids

Strategic Insights -

Researchers from Jining Medical University in China have published a groundbreaking study on the regulation of genomic imprinting in horses, donkeys, and hybrids. The study, published in the journal Biology, reveals that imprinting may work differently in various species, and that equine hybrids can be used to study epigenetic inheritance.

Key Takeaways:

  • The study found that genomic imprinting in equines is regulated by differentially methylated regions (DMRs) and long non-coding RNA (lncRNA-* * Airn* *) in mice, but not in horses and hybrids.
  • Bisulfite sequencing combined with allele-specific expression analysis revealed a tissue-specific loss of imprinting in the mule liver and hybrid brain tissues.
  • The maternal-specific expression of equine * * Igf2r* * did not rely on the canonical DMRs or lncRNA-* * Airn* *.
  • DNA methylation of a specific region called CpG island 2 (CpGI2) in the * * Igf2r* * promoter showed * * cis* * -acting inheritance, meaning that the DNA methylation patterns of the parental alleles are retained in hybrid tissues.
  • The DNA methylation of CpGI2 correlated negatively with * * Igf2r* * expression in the spleen, lung, and kidney.
  • The study provides a framework for understanding imprinting diversity in hybrids and suggests that equine hybrids can be used to study how epigenetic inheritance works.
  • The research was funded by the Medical Health Science And Technology Project of Shandong Province and Jining Medical University Scientific Research Start-up Funds For Young Doctor.

Statistics:

  • 7 tissues were analyzed in the study: heart, liver, spleen, lung, kidney, brain, and muscle.
  • 3 species were studied: horses, donkeys, and hybrids.
  • DNA methylation patterns showed * * cis* * -acting inheritance in 4 tissues: spleen, lung, kidney, and brain.
  • The correlation between DNA methylation of CpGI2 and * * Igf2r* * expression was significant in 3 tissues: spleen (R[superscript]2 = 0.8797), lung (R[superscript]2 = 0.8569), and kidney (R[superscript]2 = 0.8650).

Sources:

  • NewsRx. Reports from Jining Medical University Advance Knowledge in Biology (DNA Methylation of * * Igf2r* * Promoter CpG Island 2 Governs * * Cis* * -Acting Inheritance and Gene Dosage in Equine Hybrids). Life Science Weekly. July 8, 2025; p 4198.
  • DNA Methylation of * * Igf2r* * Promoter CpG Island 2 Governs * * Cis* * -Acting Inheritance and Gene Dosage in Equine Hybrids. Biology, 2025,14(6):678. (Biology - http://www.mdpi.com/journal/biology).