Genetic characterisation of the endangered Gochu Asturcelta pig breed using microsatellite and mitochondrial markers: Insights for the composition of the Iberian native pig stock

The extremely endangered Gochu Asturcelta pig breed was analysed to document its genetic background and to ascertain if the traditional classification of native pig of the Iberian Peninsula into the Celtic-Iberian and the Iberian groups has genetic support. Two populations of Gochu Asturcelta pig (initial and present, including 31 and 124 individuals, respectively) were typed for 17 microsatellites together with 137 individuals of four domestic pig populations (eight breeds) and Wild Boar. Gochu Asturcelta populations showed a noticeable genetic distance with the other populations analysed due to the extreme bottleneck suffered by the breed. In any case, differentiation between the two Gochu Asturcelta populations analysed was very low (FST=0.021±0.005). Morever, the two Gochu Asturcelta populations took basically the same values (1.14 and 1.13, respectively) for parameter Ng (founder genome equivalents) suggesting that the Gochu Asturcelta breed has not suffered additional genetic losses of genetic variability due to drift after the implementation of the breeding scheme. A total of 174 mtDNA control region fragments (647bp) were analysed allowing the identification of 30 different haplotypes. Gochu Asturcelta had only three different haplotypes. The most frequent haplotypes H3 (18% of the samples; assigned to Larson et al.'s haplogropup A) and H5 (25% of the samples; assigned to Larson et al.'s haplogropup C) could be identified in all the Celtic-Iberian, Iberian and Cosmopolitan pig breeds analysed. This makes difficult to ensure that the classical hypothesis explaining different origins for the native pig strains of the Iberian Peninsula has genetic support. Projection of the mitochondrial DNA genetic variability (summarised via Principal Component Analysis) on geographical maps informed that the mtDNA composition of domestic pig native of the Iberian Peninsula depicts the recent rather than the ancient history of the analysed populations.