Proceedings of the XLV Italian Society of Agricultural Genetics - SIGA Annual Congress

Salsomaggiore Terme, Italy - 26/29 September, 2001

ISBN 88-900622-1-5

Poster Abstract

A NEW GENETIC POLYMORPHISM IN THE GOAT b-LACTOGLOBULIN PROMOTER REGION

D’ANDREA M., GRAZIANO M., ANGIOLILLO A., LAGONIGRO R., PILLA F.

Dipartimento S.A.V.A, Università del Molise, Via De Sanctis, 86100 Campobasso

pilla@unimol.it

b-lactoglobulin, goat, promoter, allergy

b-lacto globulin is the major whey protein in ruminants, it is also present in the milk of other mammals, but is lacking in humans and rodents. Several variants of b-lacto globulin have been described at DNA level in bovines, ovine and goats. Bovine polymorphism has been associated with an important effect on milk production traits and cheese yield. It is known that autochthonous breeds could contain rare variants, for this reason differences in milk proteins content were investigated in some Italian local goat by HPLC. An individual variability in b-lacto globulin content was observed in “Girgentana” goat. This difference of expression could have been due to changes in the promoter region affecting the transcription level. In an attempt to understand if this correlation exists, we have characterized the promoter region of goats showing an anomalous phenotype and we have found a mutational event consisting of a single nucleotide substitution.

A PCR-RFLP genotyping procedure was developed using the BfaI restriction enzyme, for a fast detection of the mutation. The occurrence of the polymorphism, analysed in a population of 51 Girgentana goats, showed to be quite high, with a frequencies of 17%. The distribution of this new polymorphism was further studied in five different goat breeds: Garganica, Sarda, Camosciata delle Alpi, Montefalcone and Saanen. The gene frequencies for the variant was found quite variable, ranging from 8% in Garganica, to 46% in Montefalcone breed.

It is likely to hypothesise that the presence of a new mutation in the promoter region could interest a DNA-binding site for a transcription factor, reducing it binding affinity and resulting in a smaller amount of the protein, as observed in the Girgentana goat milk. Further studies are now needed to demonstrate this hypothesis and to provide evidences of whether the new polymorphism affect milk production or quality. A milk showing low contents of a protein absent in woman milk could in fact result very interesting in the treatment of milk protein allergy.