Population structure and genetic diversity of Polish Arabian horses based on pedigree data.

The research examines the genetic diversity and population structure of Polish Arabian horses, using pedigree data to identify any genetic challenges they may face. The analysis showed that despite having a large number of founders, only a few had a significant impact on the current population. This has led to a bottleneck effect and a loss in genetic diversity over time.

Methodology

• In this study, the researchers analyzed the genetic makeup of a group of Polish Arabian horses, made up of 1,498 individuals, and their 11,065 ancestors, totaling 12,543 individuals.
• The data set was compiled from comprehensive pedigree data, tracing genealogy to determine aspects such as inbreeding coefficients (F), founder effects, and diverse genetic variability measures, including the effective number of founders (f), ancestors (f), and founder genome equivalents (f).

Findings

• The data revealed a high pedigree quality, with researchers able to trace an average of 28.1 generations within the population. However, completeness of this data declined beyond the seventh generation.
• The genetic diversity parameters exhibited a significant bottleneck effect, with only 73 effective founders, indicating a significant loss of diversity over generations.
• The study showed that despite having a large number of founders (852), only a few have had a lasting influence on the current population, causing loss in genetic diversity. This signals a need to revise breeding strategies to maintain diversity.
• Slight but consistent increase in inbreeding was observed over the last century, with the average F being 5.8%, suggesting 99.6% of the reference population being inbred.
• The analysis of effective population size highlighted risks to genetic diversity, suggesting breeding goals that include a wider variety of founder lineages.

Implications

• The study indicated that stallions belonging to the reference population can be traced back to 15 distinct sire lines, while mares can be attributed to 45 unique dam lines. These numbers are significantly more than what is considered in the current breeding program.
• The findings urge for a reevaluation of traditional breeding strategies and underscore the need for ongoing monitoring and strategic breeding to maintain and enhance the genetic diversity of Polish Arabians.
• The research could potentially benefit breeders and conservationists, helping to maintain the breed’s historical significance while tackling contemporary genetic challenges.