Genetic relationship between the Nordestino horse and national and international horse breeds.

This research study focuses on understanding the genetic diversity and relationships of the Nordestino horse breed with 66 other global horse breeds, using analysis of hair samples for genotyping. Among the key revelations are considerable genetic diversity, no significant inbreeding, potential overuse of certain stallions, and strong genetic influences from other Brazilian and Iberian breeds.

Methodology and Results

The researchers collected hair samples from 393 individual Nordestino horses and genotyped these using 14 microsatellite markers.

• In their findings, they observed a high rate of allelic diversity, meaning that amongst the Nordestino breed there’s a high variety of genetic material.
• The researchers also noted that there was no significant inbreeding within the population. This lack of inbreeding is likely due to crossbreeding with other horse breeds.
• They also found that despite the population of Nordestino horses being in Hardy-Weinberg equilibrium, a global deficit of heterozygotes was noticed. This could be indicative of repeated use of the same stallions for breeding, evidenced by a high number of castrated males in the population.

Genetic Relationships

The study identified strong correlations between the Nordestino horse breed and other national and international horse breeds.

• Within Brazil, the Nordestino horse showed a close genetic relationship with the Campolina, Mangalarga Marchador, and Mangalarga breeds. This is attributed to recent introgressions or the introduction of new genetic material into the Nordestino population from these breeds.
• Concerning international breeds, the Sorraia breed, an Iberian horse breed, showed significant influence on the Nordestino horse’s genetics.

Implications of the Study

The information gleaned from this study holds important implications for future conservation programs:

• The broad genetic diversity of the Nordestino horse strengthens its potential for sustainable existence and resiliency against health threats that could exploit a lack of genetic diversity.
• The absence of significant inbreeding suggests a healthier population overall. The problem of inbreeding, common in other animal populations, often leads to health problems and the emergence of undesirable traits.
• The indication of overuse of certain stallions for breeding shines a light on an area where intervention might be useful to ensure continued genetic diversity.