Abstract: The objectives of the present study were to analyze the influence of the stallions employed in the Dülmen wild horses on the genetic diversity and population substructure using Bayesian cluster analysis. The Dülmen wild horse is maintained as a unique horse population exposed to the natural conditions all year round in the Merfelder Bruch near Dülmen in Westphalia, Germany. Stallions selected for breeding have to prove their abilities to survive under this harsh environment. We used multilocus genotypic information from a set of 29 autosomal microsatellites to determine the paternity of 185 male foals sired by nine stallions. As females could not be sampled, we could not make inferences on all yearlings and test whether there are differences in the genetic population parameters between both sexes. The mean number of progeny was 19.92 with a range of 2-32, caused by the length of the service period per stallion. The average observed and unbiased expected heterozygosity was 0.688 and 0.631, the mean number of alleles was 4.448, and Wright's F was -0.173. Pairwise genetic distances (F and Nei's unbiased genetic distances) were significant and varied between 0.038 to 0.091 and 0.085 to 0.290, respectively. Neighbor-joining dendrogram plots clustered a large proportion of the paternal progeny groups in different branches. Posterior Bayesian analyses using seven paternal half-sib groups with 10-74 members supported a maximum of six clusters, with two paternal progeny groups not differing, and a median of five clusters, with two groups of two sires each falling into the same clusters. When sires were employed in non-consecutive years, progeny from these different years of the same sires were grouped in the same cluster, whereas the progeny of one sire from two consecutive years were in different clusters. We were able to distinguish male progeny from Dülmen wild horse stallions and to show the effects of stallion use on the genetic substructure in the Dülmen wild horse herd. In conclusion, the analyses showed the genetic potential of the Dülmen wild horse stallions to maintain a high genetic diversity and also the effects in which breeding seasons and for how long stallions are used to sire foals. The selection of stallions may be sensitive for the further development of genetic diversity and preserve this closed population as a valuable resource for further studies on the evolution of the horse.
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The research explores how the choice of breeding stallions influences the genetic diversity and structure of the Dülmen wild horse population in Germany. Using genetic data from male foals sired by different stallions, the authors identify distinct clusters indicating impacts of individual stallions on the group’s overall genetics.
Research Methods
The researchers collected genotypic information from 29 autosomal microsatellites of 185 male foals in the Dülmen wild horse population. These foals were sired by nine different stallions who’ve proven their survival skills in the harsh environment of Merfelder Bruch.
With the collected data, they conducted a Bayesian cluster analysis to study the genetic diversity and population substructure, essentially separating the offspring of each stallion into distinct groups based on their genetic similarity.
However, without female samples, the researchers were unable to make any inferences about the possible differences in genetic parameters between the sexes.
Key Findings
The data showed that the number of offspring sired by each stallion varied from 2 to 32. This was due largely to the differing lengths of service periods for each stallion in the breeding process.
The average observed heterozygosity (representing genetic diversity within a population) was calculated to be 0.688 while the unbiased expected heterozygosity was 0.631. The mean number of alleles was 4.448.
Pairwise genetic distances were found to be significant, varying between 0.038 to 0.091 and 0.085 to 0.290, respectively. These variations indicate differing degrees of genetic similarity between the offspring groups.
The Bayesian analysis grouped the offspring into a maximum of six clusters, indicating distinct genetic subgroups within the population.
Offspring of one sire were grouped in the same cluster when the sire was used in non-consecutive years, while offspring from two consecutive years fell into different clusters.
Implications
This study demonstrates that stallion choice greatly influences the genetic diversity and structure within the Dülmen wild horse population. Different stallions seemingly establish distinct genetic clusters within the population.
The research highlights the importance of careful stallion selection for breeding, as it has implications for the future genetic diversity and preservation of this distinct horse population.
The stallions of Dülmen wild horses have the genetic potential to maintain high genetic diversity within the herd. However, factors like the breeding season and the duration of a stallion’s use can also affect the genetic structure of the herd.
The closed population of Dülmen wild horses provides a valuable resource for future studies on horse evolution, and the maintenance of its genetic diversity is crucial.
Cite This Article
APA
Duderstadt S, Distl O.
(2024).
Influence of Sires on Population Substructure in Dülmen Wild Horses.
Animals (Basel), 14(19), 2904.
https://doi.org/10.3390/ani14192904
Institute of Animal Breeding and Genetics, University of Veterinary Medicine Hannover (Foundation), 30559 Hannover, Germany.
Distl, Ottmar
Institute of Animal Breeding and Genetics, University of Veterinary Medicine Hannover (Foundation), 30559 Hannover, Germany.
Grant Funding
TiHo-Di-Ho/2012-15 / Institute of Animal Breeding and Genetics, University of Veterinary Medicine Hannover (Founda-tion)
Conflict of Interest Statement
The authors declare no conflicts of interest.
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