Autochthonous pig breeds are usually reared in extensive or semi-extensive production systems that might facilitate contact with wild boars and, thus, reciprocal genetic exchanges. In this study, we analysed variants in the melanocortin 1 receptor (MC1R) gene (which cause different coat colour phenotypes) and in the nuclear receptor subfamily 6 group A member 1 (NR6A1) gene (associated with increased vertebral number) in 712 pigs of 12 local pig breeds raised in Italy (Apulo-Calabrese, Casertana, Cinta Senese, Mora Romagnola, Nero Siciliano and Sarda) and south-eastern European countries (Kr skopolje from Slovenia, Black Slavonian and Turopolje from Croatia, Mangalitsa and Moravka from Serbia and East Balkan Swine from Bulgaria) and compared the data with the genetic variability at these loci investigated in 229 wild boars from populations spread in the same macro-geographic areas. None of the autochthonous pig breeds or wild boar populations were fixed for one allele at both loci. Domestic and wild-type alleles at these two genes were present in both domestic and wild populations. Findings of the distribution of MC1R alleles might be useful for tracing back the complex genetic history of autochthonous breeds. Altogether, these results indirectly demonstrate that bidirectional introgression of wild and domestic alleles is derived and affected by the human and naturally driven evolutionary forces that are shaping the Sus scrofa genome: autochthonous breeds are experiencing a sort of 'dedomestication' process, and wild resources are challenged by a 'domestication' drift. Both need to be further investigated and managed.

O porco dos Balcãs de Leste (EBS) é a última raça suína indígena da Bulgária que resta. É um porco “tipo banha” fenotipicamente similar ao javali com uma excelente capacidade de adaptação a condições extensivas. Atualmente (2016) a população da raça é de 1114 porcas e 48 varrascos e por essa razão o EBS é considerado como “em perigo”. Esta raça habita partes florestais do país nas encostas do leste de Stara Planina Mt. (Os Balcãs) e Strandzha Mt. Da mesma forma que o porco selvagem, o porco EBS caracteriza-se pela sua maturidade tardia – a idade ao primeiro parto ulatrapassa os 500 dias. Durante a sua vida reprodutiva esta raça local tem, em média, 5,2 ninhadas. A prolificidade varia de 6 a 8 leitões nascidos vivos e 5-6 leitões desmamados. Os animais EBS atingem um peso corporal de 100kg com cerca de 14 meses. Os valores médios caracterizadores da qualidade da carcaça aos 100kg de peso são os seguintes: carcaça – 56,7kg (determinada após a remoção da pele, cabeça, pernas pelo curvilhão e chispe e todas as vísceras), total de carne com ossos – 41,8kg (73,4% da carcaça) e gordura – 15,08kg (26,6% da carcaça).

The East Balkan Swine (EBS) is the only indigenous pig breed in Bulgaria. We analyzed the mitochondrial DNA (mtDNA) control region and 21 microsatellite loci for 198 individuals from 11 farms in Bulgaria. Obtained 11 mtDNA haplotypes including three novel ones were grouped to two major clades, European clade E1 (146/198 individuals, 73.7%) and Asian clade A (52/198, 26.3%). The mixture of the two clades may have resulted from historical crossbreeding between the European and Asian pig breeds. Clade A was frequent in southeastern Bulgaria (Burgas Province), but less frequent or absent in northeastern Bulgaria (Varna and Shumen Provinces). The distribution of Europe‐ and Asia‐specific haplotypes relative to EBS farm locations could be attributed to regional differences of breeding systems (e.g., crossbreeding with imported commercial pigs). A microsatellite analysis showed high heterozygosities for all the EBS farms, and negative inbreeding coefficients presumably due to crossing with commercial pigs or wild boars and/or efforts to reduce inbreeding by farmers. Bayesian clustering analyses showed that all farm populations are genetically well distinguishable from one another. Although diversity has been maintained by the efforts of farmers and a breeding association, the effective population size remains small, and conservation efforts should be continued.