Iberian origins of New World horse breeds.

This research paper focuses on investigating the genetic connection between horses from the Iberian Peninsula and those found in the New World (the Americas). The study relies on mitochondrial DNA (mtDNA) analysis of 153 samples from 30 different horse breeds and reports a higher frequency of Iberian genetic markers, signifying Iberian horses’ influential role in New World horse populations.

Study Methodology

• The researchers collected DNA samples from a total of 153 horses, which represented 30 different breeds from the Iberian Peninsula and the New World.
• They sequenced fragments of the mitochondrial DNA (mtDNA) control region of these samples. Mitochondrial DNA is inherited exclusively from the mother and is thus useful in studying maternal lineage and genetic diversity.

Findings

• The researchers identified 54 different haplotypes, which are unique sets or groups of genes inherited from a single parent. These were further grouped into seven haplogroups.
• The Menorquina, Sorraia, and Sulphur Mustang breeds showed less genetic variation, indicating potential bottlenecks in their genetic lineage or a limited number of original maternal lineages (founders).
• The Iberian breeds displayed higher genetic diversity than both South and North American breeds. This suggests that the Iberian breeds have a longer and more varied breeding history.

Implications

• Despite the evidence showing multiple origins for New World horses, Iberian haplotypes were found at a high frequency. This supports the historical assertion that horses from the Iberian Peninsula were brought over to the New World during the 15th Century and contributed significantly to the genetic makeup of contemporary New World horse breeds.

Conclusion

• This study provides valuable genetic insights into the maternal lineage of New World horse breeds, particularly identifying a strong Iberian influence. Despite their mixed origins, the presence of Iberian haplogroups in their DNA serves as evidence of the major role played by Iberian horses in their history and genetic diversity.