engleski

POSSIBILE HYBRIDIZATION BETWEEN CROATIAN AUTOCHTHONOUS PIG BREEDS AND THEIR WILD ANCESTORS

Pigs are one of the first domesticated animals, with various domestic breeds, genetically related to their free living wild relatives. Hybridization between them is reported in different European countries, with negative consequences such as, for example: altered phenotype, transmission of diseases shared with livestock, and loss of adaptive genetic diversity. Until recently two autochthonous pig breeds (Black Slavonian and Turopolje pigs), widespread in continental Croatia regions were reared in semi-wild conditions. They are well adapted to the environment, and the production system was based on a low food input and utilization of local natural food sources to reduce the cost, so farmers traditionally reared them in the open. By scoring 14 microsatellite loci in 116 individuals we analyzed genetic diversity in five animal groups and tested for potential hybridization. A Bayesian approach implemented in the program STRUCTURE identified separate clusters for wild boars and for the two autochthonous pig breeds (K=3). Estimated pairwise FST values between all pairs of populations, with P<0.001, indicated genetic differentiation between them. The results show no signal of hybridization between wild boar and domestic pigs from these two breeds, which is not surprising, since the number of pigs from these breeds is relatively low and it is small the chance that they would come into contact with wild boars. Our result is perhaps due to the power of the used analysis, but nevertheless we cannot exclude that some low level of hybridization occurred in the past and possibly still occur today, because, the STRUCTURE algorithm should, in principle, only detect recent hybridization events. The repeatedly low proportion of hybridization (<5%) is similar to what observed in other parts of Europe, and confirms that the contribution of hybridization is marginal. However, the extensive, nomadic behaviour of reared domestic pigs in the forest represents a constant risk for the genetic integrity of the wild population. Thus, permanent genetic monitoring using DNA markers and admixture analyses is crucial for conservations programs to avoid loss of native biodiversity

hybridization; genetic diversity; wild boar; autochthonous pig

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