Demystifying the Genetic Origins of the Mangalarga Horse Through the Influential Stallion Turbante J.O.

The research investigates the genetic origins of the Mangalarga horse breed, specifically focusing on the influential stallion, Turbante J.O, and challenges popular breed history by using genomic analysis instead of traditional pedigree-estimated information.

Methodology

• The researchers genotyped Turbante J.O., an influential stallion of the Mangalarga breed, and 29 other registered Mangalarga individuals. Genotyping was conducted using a commercially available ancestry service.
• DNA for this study was extracted from frozen semen samples of the notable sire.
• The genomic ancestries of Arabian, Thoroughbred, Saddlebred, and Hanoverian breeds were utilized for comparison.
• The team analyzed the pedigree-based inbreeding coefficient (F) of Turbante J.O. and 17 other Mangalargas.

Results

• The pedigree- estimated inbreeding coefficient (F) of Turbante J.O. was found to be 18.5%. However, the genomic-based inbreeding coefficient was significantly higher, found to be 33%. This discrepancy between the two estimates suggests errors in pedigree-estimated inbreeding coefficients.
• Despite the general belief that Turbante J.O. may have been sired by an unknown Hanoverian, genomic analysis suggested 100% Iberian ancestry and 99% in common with other Mangalarga individuals. There was no evidence of Hanoverian parentage.
• Only about 3% of his ancestry was found to reflect Thoroughbred and Arabian heritage, based on the pedigree-based co-ancestry coefficients.

Significance

• The inconsistency between pedigree and genomic ancestry estimates highlighted the limitations of relying solely on pedigree records for determining breed lineage or estimating inbreeding.
• The findings may have implications for the maintenance of genetic diversity in the Mangalarga breed. The high genomic relatedness suggests that selective outbreeding (breeding of unrelated or less closely related individuals) could be beneficial in preserving variety within this breed.