Genetic Structure Analysis of the Pura Raza Español Horse Population through Partial Inbreeding Coefficient Estimation

摘要

The Pura Raza Español horse (PRE) is an autochthonous Spanish horse recognized as an official breed since the 15th century. In 1912, with the creation of its studbook, it became a closed population (only animals belonging to the breed acts as breeders: 23,530 stallions and 75,870 mares), in which relatedness between individuals and inbreeding has tended to increase. Inbreeding estimation measures the probability in an individual of possessing, in one gene, two identical alleles derived from a common ancestor. Each common ancestor provides part of the descendant’s total inbreeding (partial inbreeding coefficient, F ). This work analyzes the F , calculated using a recently developed approach (based on founders and Mendelian sampling of the non-founders) in the whole PRE population. The identification of 10,244 common ancestors and their relationship with the seven most influential individuals of the breed allowed us to determine that a genetic bottleneck due to an unequal contribution over the generations occurred. Computing F has being an important tool to determine which are the breeding animals, with more or less massive use, whose are determining a loss of genetic variability in the population at each moment and has enabled us to expand our knowledge about PRE genetic demographic evolution.