Mitochondrial Profiles of the East Bulgarian and the Pleven Horse Breeds.

The study presents the first collection of genetic information on two modern horse breeds, the Pleven and East Bulgarian, from the plain regions of Bulgaria. The genetic profile displayed differences in the two breeds, likely due to various horse breeds involved in their formation.

Overview of the Research

• The research aimed to gather, for the first time, molecular data on two horse breeds from the plain regions of Bulgaria. Bulgaria has a rich cultural heritage in horse breeding, tracing back to prehistoric and historic times. Despite its significance, there was no available molecular data on Bulgarian horses from these regions until this study was conducted.
• The researchers took genetic samples from a total of 50 horses from different families belonging to the Pleven and East Bulgarian breeds. The Pleven breed was found predominantly in the Danubian Plain, and there were 11 horses sampled from this breed. The East Bulgarian breed was mainly found in the Shumen district, with 39 horses sampled from this breed.

Methods

• The horses from both the breeds were genotyped. The method used for this process was based on the mitochondrial D-loop region, an area of the mitochondrial genome commonly used for studying genetic diversity and relationships among animal populations.

Results

• The results indicated that the Pleven horse largely carries the European haplogroup L (45.45%), followed by the Middle East haplogroup C (27.27%). Haplogroups are a group of similar haplotypes, often used to describe genetic populations — in this case, distinct horse populations.
• However, the East Bulgarian horse breed showed a near-equal frequency of European haplogroup L (33.33%) and the Central Asiatic haplogroup Q (35.90%). This suggests a significant mix of different genetic populations in the East Bulgarian breed.

Conclusion

• Analysis of both the horse breeds revealed unique genetic profiles. The major difference is that the East Bulgarian horse breed showed a mixed genetic profile, with a massive admixture with the Asiatic-type haplogroup Q and high haplogroup diversity. This might be due to the various horse breeds involved in their formation, demonstrating the impacts of cross-breeding with other horse populations.