Analysis of melanocortin 1 receptor (MC1R) gene polymorphisms in some cattle breeds: their usefulness and application for breed traceability and authentication ofParmigiano Reggiano cheese

Abstract

In cattle, the MC1R gene has been the subject of several studies with the aim to elucidate the biology of coat colour. Then, polymorphisms of this gene have been proposed as tools for breed identification and animal products authentication. As a first step to identify breed specific DNA markers that can be used for the traceability of mono-breed dairy cattle products we investigated, using PCR-RFLP and PCR-APLP protocols, the presence and distribution of some alleles at the MC1R locus in 18 cattle breeds for a total of 1360 animals. For each of seven breeds (Italian Holstein, Italian Brown, Italian Simmental, Rendena, Jersey, Reggiana and Modenese) a large number of animals (>70) was genotyped so the obtained results can be considered with more confidence. Allele Ed was identified only in black pied cattle (Italian Holstein and Black Pied Valdostana). Allele E (this nomenclature includes all alleles except Ed, E1 and e) was observed in Italian Brown, Rendena, Jersey, Modenese, Italian Simmental, Grigio Alpina, Piedmontese, Chianina, Romagnola, Marchigiana, Swedish Red and White and Danish Red. Allele E1 was identified in Italian Brown, Rendena, Grigio Alpina, Piedmontese, Swedish Red and White and Danish Red. The recessive allele e, known to cause red coat colour, was fixed in Reggiana and almost fixed in Italian Simmental. This allele was observed also in Italian Holstein, Italian Brown, Rendena, Jersey and Modenese albeit with low frequency. Moreover, this allele was detected in Valdostana, Pezzata Rossa d’Oropa, Piedmontese, Romagnola, Swedish Red and White, Danish Red, Charoleis and Salers. In the case of the Reggiana breed, which is fixed for allele e, the MC1R locus is highly informative with respect to breeds that carry other alleles or in which allele e is at very low frequency. In theory, using the MC1R locus it is possible to identify the presence of milk from some other breeds in Parmigiano Reggiano cheese labelled as exclusively from the Reggiana breed. This possibility was practically tested by setting up protocols to extract and analyse polymorphisms of the MC1R locus in several dairy products, including Parmigiano Reggiano cheese cured for 30 months. The lower detection limit was estimated to be 5% of non expected DNA. This test can represent a first deterrent against fraud and an important tool for the valorisation and authentication of Parmigiano Reggiano cheese obtained from only Reggiana milk.