Technical note: simultaneous identification of CSN1S2 A, B, C, and E alleles in goats by polymerase chain reaction-single strand conformation polymorphism.

Most variability in goat caseins originates from the high number of genetic polymorphisms often affecting the specific protein expression, with strong effects on milk composition traits and technological properties. At least 7 alleles have been found in the goat alpha(S2)-CN gene (CSN1S2). Five of them (CSN1S2A, CSN1S2B, CSN1S2C, CSN1S2E, and CSN1S2F) are widespread in most breeds, whereas the other 2 (CSN1S2D and CSN1S2*0) are rarer alleles. Four different PCR-RFLP tests are needed to detect all of these variants at the DNA level. The objective of this study was to develop and validate a rapid method for typing 4 of the 5 most-common goat CSN1S2 alleles by means of PCR-single strand conformation polymorphism (SSCP). The method was validated by analyzing 37 goat samples at the protein and DNA level, respectively, by milk isoelectrofocusing and PCR-RFLP methods already described. The genotypes obtained using the PCR-SSCP approach were in full agreement with those obtained by the validation analyses. The newly developed PCR-SSCP approach provides an accurate and inexpensive assay highly suitable for genotyping goat CSN1S2.