Genetic Diversity, Parentage Verification, and Genetic Bottlenecks Evaluation in Iranian Turkmen Horse Breed.

The research conducted a genetic evaluation on Turkmen horses to assess their genetic diversity and to identify any potential recent genetic bottlenecks. It was discovered that, despite unplanned breeding, the breed demonstrated high genetic variability, low levels of inbreeding, and no recent genetic bottlenecks.

Genetic Evaluation and Diversity

• The study included 565 Turkmen horses, all of which were assessed using 12 microsatellite markers. This method was used to characterize the within-breed diversity.
• The estimated mean allelic diversity was 9.42 ± 1.78 per locus. In the genotyped samples, there were a total of 131 alleles.
• The breed showed high genetic variability, as suggested by high values of the effective number of alleles (4.70 ± 1.36), observed heterozygosity (0.757 ± 0.19), expected Nei’s heterozygosity (0.765 ± 0.13), and polymorphism information content (0.776 ± 0.17).

Parentage Verification

• With an average value of 99.96%, the estimated cumulative probability of excluding wrongly named parents was high. This high percentage indicates the effectiveness of the applied markers in resolving the parentage typing in the Turkmen horse population.
• A likelihood-based method confirmed all selected animals as correctly identified. There was no evidence of misidentification in the paternity testing results.

Inbreeding and Genetic Bottlenecks

• The study found low levels of inbreeding in the Turkmen horse breed, as indicated by low values of Wright’s fixation index, F(IS) (0.012).
• Different models showed a significant heterozygote excess, a condition suggesting that the Turkmen horse population is not in mutation-drift equilibrium.
• The Mode-shift indicator test did not find any recent genetic bottlenecks, as evidenced by a normal ‘L’ shaped distribution for allelic class and proportion of alleles.
• However, the discrepancy observed in the results regarding genetic bottlenecks necessitates further research.

Conclusion

• The research concludes that despite unplanned breeding, the Turkmen horse breed maintains sufficient genetic variability, which could be valuable for future breeding programs. The breed also exhibits low levels of inbreeding and no recent genetic bottlenecks.