Comparative Transcriptome Profiling Analysis Uncovers Novel Heterosis-Related Candidate Genes Associated with Muscular Endurance in Mules.
Authors: Gao Shan, Nanaei Hojjat Asadollahpour, Wei Bin, Wang Yu, Wang Xihong, Li Zongjun, Dai Xuelei, Wang Zhichao, Jiang Yu, Shao Junjie
Journal: Animals : an open access journal from MDPI
Summary
# Editorial Summary: Heterosis-Related Gene Expression in Mule Muscle Tissue Hybrid vigour in mules—the superior performance often observed in horse-donkey crosses compared to either parent species—remains poorly understood at the molecular level, yet understanding these mechanisms could inform selective breeding and management strategies. Researchers conducted a genome-wide transcriptome analysis across muscle, brain, and skin tissue from mule crosses, examining both gene expression patterns and alternative splicing variations to identify which genes might explain the heterotic advantage. The investigation revealed striking results: 86.1% of differentially expressed genes and 87.2% of alternative splicing variants in muscle tissue demonstrated over-dominance or dominance effects—meaning mule alleles produced stronger effects than either parent's alleles alone. Notably, genes associated with the "muscle contraction" pathway were significantly enriched amongst both gene expression and splicing variants in muscle tissue specifically, suggesting this metabolic pathway underpins the endurance capabilities mules are renowned for. These findings provide a molecular framework for understanding heterosis in equine hybrids and may guide future breeding programmes seeking to optimise muscular endurance traits, whilst offering farriers and veterinarians insight into the physiological basis of mule athleticism and resilience.
Read the full abstract on PubMed
Practical Takeaways
- •Mules' superior muscular endurance compared to their parents may be explained by specific gene expression patterns and alternative splicing mechanisms in muscle tissue, suggesting heterosis provides genuine physiological advantages for work performance
- •Understanding the genetic basis of heterosis could inform selective breeding strategies for hybrid equines if similar molecular mechanisms are confirmed across different crosses
- •The muscle contraction pathway appears central to heterosis expression in equine hybrids, offering potential targets for future research into optimizing performance traits
Key Findings
- •86.1% of differentially expressed genes in mule muscle showed over-dominance or dominance effects
- •87.2% of differential alternative splicing genes in mule muscle demonstrated over-dominance or dominance patterns
- •The muscle contraction pathway was significantly enriched among both DEGs and DAS genes in mule muscle tissue
- •Transcriptome profiling identified novel candidate genes potentially responsible for heterosis-related muscular endurance improvements in donkey-horse crosses