A lost Sorraia maternal lineage found in the Lusitano horse breed.

The research article explores a common maternal lineage found among the Portuguese Sorraia and Lusitano horse breeds. The study, examining variations in the Lusitano mitochondrial DNA lineages, makes important revelations about the relationship between the Sorraia and other Iberian breeds.

Methodology and Findings

• The researchers used a sample of 16 descendants from a Sorraia founder mare, known as Pomba. These descendants are part of the Lusitano breed’s living population and were identified using the most recent studbook information of this breed. A 416bp control region sequence was taken from the horses for analysis.
• The analysis revealed that all of the horses shared the same haplotype. In genetics, a haplotype refers to a group of genes within an organism that was inherited together from a single parent.
• This shared haplotype belonged to a haplogroup that many authors have classified as having predominantly Iberian, South American, and North African haplotypes. This point indicates a strong connection between the Sorraia horse and the wider Iberian breeds.

Study Implications

• The results of this study shine a light on how indistinct the boundaries of breed establishment can be, especially within the same geographical region. The common haplotype discovered among the Sorraia and Lusitano breeds suggests that breeders likely used the same founders for different breeds in the past.
• This practice of using same founders can explain why haplotypes are often shared among recent horse breeds. It also led to the observed inconsistency between mtDNA sequences and different horse breeds or geographical regions.
• In essence, the study reveals how the forces of selective breeding, shared founders, and geographical location can shape the genetic profiles of different horse breeds, using the Sorraia and Lusitano breeds as an example.