Analisi di due geni (KITeMC1R) che influenzano il colore del mantello nel suino e potenziali applicazioni per la tracciabilità dei prodotti di suino nero siciliano

Nero Siciliano is an autochthonous Sicilian pig breed. The animals are usually completely black but a few show white portions mainly in the face or in the fore legs. Here we analysed two coat colour affecting genes, KIT and melanocortin 1 receptor (MC1R), with the aim to i) characterize the Nero Siciliano breed at these two loci, ii) identify mutations associated with the presence of white coat colour patterns and iii) identify DNA markers useful for breed traceability of meat obtained from Nero Siciliano pigs. Two samples were considered in this study: i) 104 pigs collected from 13 different farms, without recorded information on coat colour; ii) 72 pigs sampled from 4 farms with recorded coat colour data. The intronless porcine MC1R gene was analysed amplifying three PCR fragments containing the polymorphic sites that make it possible to distinguish the E+, ED1, ED2, EP and e alleles. Five alleles (ED2, EP, ED, e and E+) have been identified at the MC1R locus, thus markers at this gene cannot be used for Nero Siciliano product traceability. We genotyped 97 Nero Siciliano pigs (25 with white portions) for the splice site mutation of the intron 17 of the KIT gene that is associated with the Dominant White I allele. These animals were also analysed for the presence of the duplication of the same gene. None of the pigs carried the splice site mutation while 7 out of 25 animals with white portions were positive for the duplication test. Then, 20 of the 21 exons of the KIT gene (including intronic regions) were sequenced in eight Nero Siciliano pigs with different colour patterns and in one Large White animal. The results suggest that the presence of white portions in Nero Siciliano pigs might be only in part due to mutations in the KIT gene.