Genetic diversity and population structure in remnant subpopulations of Nordestino horse breed

This study analyzed four remnant subpopu- lations of Nordestino horse breed to detect genetic structure and diversity through 14 microsatellite markers. Hair root follicles from a total of 393 horses were collected. There were 61 animals from Salitre Valley (JUAZ-BA) located at Bahia state, 89 from North and Central North ecoregions located at Piaui state (NCEN-PI), 185 animals from Sertao and Sertao do Sao Francisco ecoregions (SERT-PE) and 58 animals from Agrestina city (AGRE-PE) located at Pernambuco state. Genetic diversity, genetic differentiation and bottleneck effects were examined in the 4 remnant subpo- pulations of Nordestino horse breed. There was high allelic diversity and the F is value did not show evidence of a significant predominance of mating among relatives, probably because of crossbree- ding among populations. Recent bottleneck effects were not detected in the 4 subpopulations, but the IAM and TPM model did suggest a bottleneck effect. This may be a reflection of the decreased number of breeding animals caused by castration of males, mechanization processes and changes in life style in the rural areas. The bottleneck event was not enough to lead a genetic differentiation among the 4 remnant subpopulations of Nordestino horse. There was no evidence of genetic diffe- rentiation, so the 4 subpopulations formed one genetic group.