Influence of Sires on Population Substructure in Dülmen Wild Horses.
Authors: Duderstadt Silke, Distl Ottmar
Journal: Animals : an open access journal from MDPI
Summary
# Editorial Summary: Sire Influence on Dülmen Wild Horse Population Genetics Using 29 microsatellite markers to assign paternity across 185 male foals, Duderstadt and Distl investigated how nine breeding stallions shape genetic structure within the Dülmen wild horse population—a semi-feral German herd maintained under natural conditions year-round. Bayesian cluster analysis revealed that individual sires create distinct genetic substructures, with paternal half-sibling groups clustering separately in dendrogram analysis; notably, progeny from the same stallion used in non-consecutive breeding seasons grouped together, whilst offspring from consecutive years diverged genetically. The population maintained robust heterozygosity levels (observed 0.688, expected 0.631) and moderate allelic diversity (mean 4.448 alleles per locus), though significant pairwise genetic distances between paternal lineages (FST 0.038–0.091) confirm marked population subdivision driven by stallion selection. For those managing closed or semi-feral populations, these findings underline that stallion selection protocols—particularly decisions around breeding tenure and annual rotation—directly influence genetic partitioning and ultimately conservation potential; practitioners should consider that strategic use of sires across interrupted breeding seasons may better maintain overall population diversity than consecutive deployment, though larger datasets including females are needed to confirm whether sex-specific patterns exist.
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Practical Takeaways
- •Selective breeding practices in closed horse populations can significantly influence genetic substructure; stallion selection and breeding scheduling should be carefully managed to maintain diversity and prevent inadvertent population stratification
- •Service period duration and timing of stallion use directly affect the genetic contribution to the herd; careful documentation and strategic rotation of breeding males preserves valuable genetic resources
- •Regular genetic monitoring of closed populations using microsatellite analysis provides objective data to guide breeding decisions and prevent loss of genetic diversity in conservation herds
Key Findings
- •Nine stallions sired 185 male foals with mean progeny of 19.92 (range 2-32), demonstrating variable reproductive success based on service period length
- •Bayesian cluster analysis supported a maximum of six genetic clusters and median of five clusters among paternal progeny groups, indicating significant population substructure
- •Observed heterozygosity averaged 0.688 with mean of 4.448 alleles per locus, and Wright's FIS of -0.173 indicated high genetic diversity maintenance
- •Stallion breeding timing affected genetic clustering: non-consecutive years produced same-cluster progeny while consecutive years from one sire produced different clusters