Pedigree analysis in the Austrian Noriker draught horse: genetic diversity and the impact of breeding for coat colour on population structure.

The article discusses a study into the genetic diversity and population structure of the Austrian Noriker draught horse, focusing on the impact of breeding for different coat colours. This was done through pedigree tracing, which revealed significant variability across different regions and coat colours, pointing to the value of this diversity in preserving this endangered breed.

Research Background

In this research, the focus was on the Austrian Noriker draught horse which is a unique breed from Austria. The study aimed to understand the genetic diversity and population structure of this breed, particularly exploring the impact of breeding efforts focused on different coat colors. The research involved pedigree tracing of all 2808 horses within the breed to the founding animals to gain insights into the breed’s genetic history.

Methodology

A total of 1991 founders were identified in the traced pedigree, with the longest record spanning 31 generations and an average of 12.3 complete generations. The population structure was analyzed both by the geographical regions of Austria and the coat color groups prevalent in the breed. The seven breeding regions considered were Carinthia, Lower Austria, Salzburg, Styria, Tyrol, Upper Austria and Vorarlberg. The six coat colour classifications were Bay, Black, Chestnut, Roan, Leopard, Tobiano.

Findings

• The inbreeding coefficients, a measure of genetic variation, showed variability both across the geographical regions and coat color groups. The coefficients for the regions ranged between 4.5% and 5.5% while the coefficients for the color groups varied from 3.5% to 5.9%.
• Other measures of genetic diversity like the number of effective ancestors, founders, and founder genomes also showcased varying genetic backgrounds across sub-populations.
• The co-ancestry levels indicate that the Salzburg population may be seen as the original stock, with other sub-populations showing a high relationship with horses from this area.

Contributions and Implications

The research concludes that the current breeding focus in the 21st-century leans more towards stabilizing selection rather than maximizing genetic gains. It suggests that the demographic factors coupled with different coat colors have played a critical role in maintaining the existing genetic diversity in this endangered breed. These findings are relevant for future management and breeding strategies focused on preserving and strengthening the Austrian Noriker draught horse breed.