Caracterização genética de remanescentes da raça equina nordestina em mesorregiões dos estados da Bahia, Pernambuco e Piauí através de marcadores microssatélites

Abstract

The present research aimed characterizes genetically 4 remnant subpopulations from the Nordestino horse breed and infers which national and exotic horse breeds influenced in the Nordestino horse breed formation. A total of 393 animals that were split into 4 subpopulations at eco-regions belong to Bahia (called JUAZ-BA), Pernambuco (divided into AGRE-PE and SERT-PE) and Piauí (called NCEN-PI). The animals were genotyped with 14 microsatellite markers. Arab horse breed’s data were used as outgroup for genetic differentiation analyze among the 4 subpopulations remaining from Nordestino horse breed. Przewalski horse’s data were used as outgroup to infer which horse breeds to take part in the formation of the Nordestino horse breed. There was a high genetic diversity in the 4 remnant subpopulations of Nordestino horse breed, probably it may be due to outbreed and/or mating among unrelated individuals. No significant deviations from Hardy-Weinberg Equilibrium with the 4 subpopulations were under random mating. No genetic differences among the 4 subpopulations, so they represented a sample from the same gene pool according STRUCTURE software, AMOVA, Factorial Correspondence Analysis (FCA) and genetic distances: DA and DR. The 4 subpopulations could be considered part of a single large random mating genetic population because of gene flow and recent history of formation from the Nordestino horse breed. Gene diversity excess was observed suggesting the 4 subpopulations may undergo bottleneck effects (demographic and genetic); however the bottleneck did not occur in a recent period. The results were similar for genetic diversity and bottleneck analyses when the 4 subpopulations were considered as being just one population. Campolina, Mangalarga Marchador e Mangalarga were Brazilian horse breeds closer to Nordestino one. Therefore, those breeds took part in the genetic basis of the Nordestino horse. Among Iberian horse breeds, the Sorraia horses seem to exert greater influence on initial formation of the Nordestino horse breed. The microsatellite markers used in this research were satisfactory because of PIC (Polymorphic Information Content) values ranged from informative to highly informative to the analyzed populations.