Polymorphism of κ-Casein in Italian Goat Breeds: A New ACRS-PCR Designed DNA Test for Discrimination of A and B Alleles

Maria Feligini1*, Vlatka Cubric-Curik2, Pietro Parma1, Ino Curik3, Gian Franco Greppi1,4 and Giuseppe Enne1,5

Istituto Sperimentale Italiano »Lazzaro Spallanzani«, Laboratorio di Epigenomica Applicata (LEA), Via Giovanni XXIII, I-26900 Lodi, Italy

2Dairy Science Department, Faculty of Agriculture University of Zagreb, Svetošimunska 25, HR-10 000 Zagreb, Croatia
3Animal Science Department, Faculty of Agriculture University of Zagreb, Svetošimunska 25, HR-10 000 Zagreb, Croatia
4Istituto di Medicina Legale e Legislazione Veterinaria, Facoltà Medicina Veterinaria, Università di Milano, Via Celoria 4, I-20133 Milano, Italy
5Dipartimento di Scienze Zootecniche, Facoltà di Agraria, Università di Sassari, Via E. De Nicola, Sassari, Italy

Article history:

Received: February 21, 2002
Accepted: November 7, 2002

Key words:

ACRS-PCR, genetic polymorphism, goat, κ-casein


The objective of this study was to develop a DNA test for rapid characterisation of goat κ-casein (κ-CN) A and B variants and to study this polymorphism in Italian goat breeds. Genetic polymorphism of κ-CN gene was, in addition to isoelectric focusing, analysed according to a new technique designated as amplification created restriction site. Two alleles that differ in one nucleotide mutation (G Ø A) in exon 4 were characterised. The 167-bp PCR product surrounding the nucleotide mutation was amplified from genomic DNA and the PCR product was digested with MaeIII. After digestion the A allele gives three fragments of 77, 65 and 25 bp in comparison with the B allele which gives two fragments of 90 and 77 bp. The analysis of allele frequency distribution at κ-CN locus, based on 401 individual samples, revealed significant differences among three goat breeds from the north of Italy (Nera di Verzasca, Frontalasca and Alpine) with frequency of κ-CN B allele around 0.3, versus two goat breeds from the south of Italy (Maltese and Sarda) with frequency of κ-CN B allele around 0.5. While two goat breeds (Maltese and Nera di Verzasca) did not show significant deviations from the Hardy-Weinberg equilibrium, a highly significant excess of heterozygote genotype (AB) was observed in Alpine, Frontalasca and Sarda goats. Here the developed DNA method and observed relatively high frequency of κ-CN B allele give a prerequisite for the assessment of research related to the simultaneous estimation of the effects of composite αs1/κ-CN genotypes on milk production and cheese-making properties.

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