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An allele associated with a non‐detectable amount of αs 2 casein in goat milk
Author(s) -
Ramunno L.,
Longobardi E.,
Pappalardo M.,
Rando A.,
Di Gregorio P.,
Cosenza G.,
Mariani P.,
Pastore N.,
Masina P.
Publication year - 2001
Publication title -
animal genetics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.756
H-Index - 81
eISSN - 1365-2052
pISSN - 0268-9146
DOI - 10.1046/j.1365-2052.2001.00710.x
Subject(s) - biology , allele , casein , locus (genetics) , microbiology and biotechnology , exon , null allele , population , restriction fragment length polymorphism , genetics , gene , allele frequency , genotype , food science , demography , sociology
The goat CSN1S2 locus is characterized by the presence of three alleles, A , B and C , all associated with about 2.5 g/l of protein per allele. The SDS–PAGE analysis of 441 individual milk samples obtained from goats belonging to a population reared in Southern Italy showed that the milk produced by three goats did not apparently contain α s 2 ‐casein, whereas milk produced by 37 goats showed a less intense electrophoretic band of this casein fraction (about 50%). These results can be explained by hypothesizing the presence of another allele at this locus , CSN1S2 0 , associated with a ‘null’ content of α s 2 ‐casein. Southern blot, PCR and PCR–RFLP analyses of the DNA region containing the CSN1S2 gene of individuals producing milk with and without α s 2 ‐casein did not show differences between the two groups. As a consequence, goats producing milk without α s 2 ‐casein carry an apparently intact gene. The first results obtained by sequencing part of the CSN1S2 0 allele revealed a G→A transition at nucleotide 80 of the 11th exon which creates a stop codon and could be responsible for the absence of the α s 2 ‐casein in goat milk. This mutation eliminates a Nco I restriction site. A test based on this polymorphism has been established in order to identify carriers of the CSN1S2 0 allele.