Phased T2T horse and donkey assemblies from a mule reveal peculiar equid centromere evolution.

Complete telomere-to-telomere genomes of a horse and donkey reveal unusual centromere evolution and plasticity in equids, with notable differences in satellite DNA and protein binding.

• Why it matters: Understanding centromere structure and function is crucial for insights into chromosome stability and evolution, especially in species like equids that show atypical centromere behavior.
• What they did: The team generated high-quality genome assemblies from mule offspring, enabling detailed annotation of satellite-based and satellite-free centromeres, and analyzing centromere-associated proteins CENP-A and CENP-B across species.
• The result: Findings highlight centromeric plasticity and the absence of CENP-B association in equids, offering new perspectives on their rapid karyotypic changes and providing essential resources for advancing equine genomics research.