Genetic studies of blood markers in Przewalski’s horses.

The study investigates the genetic aspects of blood markers in the Przewalski’s horse population, using blood typing systems that have been successful in parentage testing of domestic horses. The researchers found that despite the Przewalski’s horses’ limited genetic base and high inbreeding, their average heterozygosity is comparable to that of five domestic horse breeds.

Research Design and Methodology

• The researchers carried out a blood typing study on a sample size of ninety-six Przewalski’s horses, utilising systems of inherited blood variants that have previously been effective in determining the parentage of domestic horses.
• They identified sixteen red cell antigenic factors, utilising sera created by alloimmunization (building of immunity) in domestic horses.

Inheritance Patterns

• The researchers found that these factors were inherited in six systems – A, C, D, P, Q, and U – in similar patterns to those in domestic horses.
• Analysis of family data showed autosomal and codominant inheritance at eight loci, consisting of five loci of serum protein variants (Al, Tf, Xk, Pi, and Es) and three loci of red cell proteins (PGM, PHI, and Hb).
• A serum protein locus (Gc) and two red cell protein loci (PGD and CA) seemed to be monomorphic, where they only had one form.

Analysis of Genetic Diversity

• The researchers analysed the heterozygosity, or genetic diversity, within the Przewalski’s horse population.
• Despite the small genetic base and high rates of inbreeding of captive populations of these horses, the researchers claim that heterozygosity is relatively high.
• An average heterozygosity was calculated over eighteen loci, and estimated to be around 0.320 +/- 0.05 – a figure that is comparable to what is found in five different breeds of domestic horses.