Comparative and quantitative morphology of the pig and wild boar cerebellum for identifying possible effects of domestication

Abstract

The domestic pig (Sus scrofa domesticus) stems from the Eurasian wild boar (Sus scrofa): this offers an appealing window to study microanatomical changes related to the process of domestication, the symbiotic relationship between human and animal. In this light, we quantitatively demonstrated significant microanatomical differences between pig and wild boar cerebella. Calbindin D-28, a calcium binding protein, was employed as immunohistochemical marker of the Purkinje cells. Our results showed that: (i) the foliation index, expressing the rate of cerebellar cortical folding, and the number of granular cells were not significantly different between pigs and wild boars; (ii) area of the granular layer and the molecular layer, and area of white matter were lower in pigs; (iii) the fraction area, grey matter/white matter, was higher in pigs; (iv) the Purkinje cell linear density and their soma area were higher in wild boars. Despite the morphological data alone are not sufficient to draw any final conclusions, our findings on Purkinje cells may represent good indicators of a reduction of the pig cerebellum motor and cognitive functions during the process wild boar-to-pig domestication.