New high-sensitive rhAmp method for A1 allele detection in A2 milk samples
Rodrigo Giglioti1, Gunta Gutmanis1, Luciana Morita Katiki1
1Instituto de Zootecnia (IZ), Rua Heitor Penteado, 56, Zip Code 13380-011 Nova Odessa, SP, Brazil.
Food Chemistry
|January 18, 2020
Summary
Researchers developed two methods to detect A1 and A2 beta-casein (β-casein) in milk. The rhAmp SNP genotyping assay showed higher sensitivity for identifying the A1 beta-casein variant, making it a preferred method.
Area of Science:
- Dairy Science
- Genetics
- Biotechnology
Background:
- Cows' milk contains β-casein variants A1 and A2.
- Digestion of A1 β-casein releases β-casomorphin-7, potentially causing gastrointestinal issues.
Purpose of the Study:
- To develop and compare methods for identifying A1 and A2 β-casein alleles in milk.
- To evaluate the analytical sensitivity and specificity of these methods.
Main Methods:
- Development of high-resolution melting (HRM) and rhAmp® SNP genotyping assays.
- Analysis of DNA from 45 milk samples.
- Sequencing of 10 samples for validation.
- Testing analytical sensitivity using serial dilutions of A1 allele DNA.
Main Results:
- Both HRM and rhAmp assays accurately differentiated A1 and A2 alleles.
- rhAmp demonstrated superior analytical sensitivity, detecting A1 at 2% (10 copies) compared to HRM at 10% (100 copies).
Conclusions:
- rhAmp SNP genotyping is recommended over HRM for identifying A1 and A2 β-casein alleles due to its enhanced sensitivity.
- Accurate detection of β-casein variants can inform dairy practices and consumer choices.
